What B cereus said. For low and mid profile brakes the lower the yoke the longer the virtual lever and the less pad movement for the same cable pull, less pad movement equals more force - If you imagine a horizontal line from the boss and a line from the yoke continuing through the attachment point, where they intercept is the leverage.
With wide arm canti's it makes no difference, the arms are already horizontal.

Thanks folks. Really appreciate all the advice.

I was really just looking for the views on sandblasting and powder coating / painting.

My pal at the LBS knows to plug all holes and remove everything from the frame. Bits like brake cables / shoes will be replaced as required.
( Good advice on greasing the inside of the frame ).
I also have a new front ring and rear ( old style ) cog to fit. Plus chain.

It looks like I'll go with the powder coating. And stick to black.
But all further views appreciated.

I'm looking to get the Raven ship shape for a Summer Scottish tour ( depending on my recovery from the cancer op I had last Nov. - I start a second round of Chemo next week ) and then perhaps pass it on to a Thorn enthusiast who can take it abroad for a long tour it loves. A lot of good memories are built into that bike. Only fare to let go rather than keep it tied to an old fella who can't make full use of it.

Once again, all comments appreciated.

Matt

Lovely bike, Adrian!  Good work by your Bridport firm.

Just curious:  what gearing do you have?  Thinking about the Abbotsbury Hill...

Cheers,  John

Hello John, as far as I'm aware the gearing is 26/36/46 front and 13-26 8 speed rear.  I've not tried Abbotsbury Hill yet, not the hill i live at the bottom of, Whiteway... https://climbfinder.com/en/map#lnglat=-2.6350/50.7141&climb=17293&position=13.13/50.71015/-2.63313

Adrian

On the topic of threads on the fittings for fender mounts, water bottle cages, etc., it is easy enough to clean those out with a 5mm tap.  I would not bother giving instructions to anyone on that. 

The first new frame I bought, I had to buy a tap to do that.  I do not remember if any of the other frames that I bought new needed a tap to be run through the threads or not, I do not remember because it is such a minor thing to do.

I noted above on rack bolts, fender bolts, I use thread locker.  A lot of bike shops do not even have any thread locker in the shop, that is not as common as you might think.   Water bottle cage bolts, a bunch of other fittings, I grease the threads first.  You do not think of grease as being a good way from keeping a bolt from vibrating loose, but it actually is pretty good at that because grease is very very viscous.

But a lot of this detail is more than any people you hire to do the work want to hear.  That said, in the interview before you hire the work to be done, you could ask them what they do on these topics.  If they are evasive, hire someone else.

I get detail oriented because I do 99 percent of my own work.  Last time I paid a bike shop to do some work on one of my bikes, it was to press the headset into the frame and fork on a new frame I bought, I did not own the tools I needed for that.  That was a decade ago.

If your rims are CSS, make sure that if they replace brake pads, that they know what pads to use.  If they are CSS, if it was me, I would instruct them to not do anything on the pads as most shops would not know what CSS rims are.

Adding to George's list:

Wheels

I check the wheels every few years for rim wear and spoke tension/wheel truth.

Just done a fairly extensive overhaul on my old 650B utility bike. The rear rim is at just over 14,600 kms and starting to get a bit concave, but I reckon I can still use it for a year or two. Front rim doesn't seem very worn at 9,500 kms, unlike the older rear rim it has a wear indicator. Both rims were still true, so no need for any spoke adjustment. Rims wear relatively quickly on this bike as it is my preferred choice for local riding in bad weather and/or on tracks and paths. I use the front brake more than the rear, but rear rims wear more quickly, probably because the rear wheel picks up more muck than the front.

Front hub is a SON dynohub, so I don't do any maintenance other than cleaning the outside. Rear hub is an old Sturmey Archer S5/2, so I stripped that down, cleaned and relubricated it. It still works well after 56,000 kms.

With a Rohloff, I would just check the flanges, as these can sometimes crack. Not had this happen on any of my hub gear bikes, but in 1978 I did crack a flange on a derailleur hub falling on ice.   

Transmission

The chain hadn't been maintained for two years, so I took the ChainGlider off, wiped clean the chainring and sprocket, swapped the chain for another and cleaned the inside of the ChainGlider before refitting it. The latter had picked up a certain amount of black gunk, probably from a mix of dust and chain lube. The chain I took off was black, but not measurably worn, so I cleaned/relubed it and it will be going back on next time I do an extensive overhaul. 

Pedals and bottom bracket unit didn't need any maintenance. The gear cables and housings had only been on for a few years, and still worked smoothly, so I didn't replace them.

Brakes

I dismantled, cleaned and regreased the cantilever brakes, but I needn't have bothered as the grease on the insides was still good. These brakes had been on the bike for 35,000 kms. The old Deore XT brake levers from the early 1980's (64,500 kms) just needed a squirt of silicone lube and very slight tightening to reduce play. The brake cables and housings had been on the bike for more than twenty years, so I replaced with new, the rear inner cable was a bit rusty so I should probably have done this sooner. I replaced the brake pads, which had been on the bike for about 4 years, they were very worn.

Headset

Dismantled (except for the fixed cups), cleaned and regreased. This is a Stronglight X headset with needle bearings with 51,000 kms of use.

Stem/bars and seat post/saddle

Took the stem out of the fork, seat post out of the frame, put some anti-seize grease on them and refitted them. The Tange straight handlebars (steel) had a bit of rust after 55,500 kms but not too bad so I didn't change them. The Ergon handlebar grips were worn, so I replaced these with ESI Fatty grips, which don't last so long but are a bit more comfortable. The B66 Champion saddle (69,500 kms) just needed its regular treatment - I use Nikwax rather than the recommended Proofide.