Hi to all,

I am in the process of selling my Thorn Brevet Special. 

It's a Lee Cooper frame for which the paint has seen better days !

Reynolds 531 DS frame and 531 forks.

I know they are quite rare now and rarely sold.

It's pretty much original but some of the drive train has been replaced.  i.e.  The chain set, chain and rear cassette.  Also it has an adjustable Ergon stem; I've no idea where the original 3ttt one went.  TBH, I'm unsure if it would have come with a Suntour XCE front mech, I suspect it would have been Deore LX like most of the group set and hubs.

SP measures 50 cm c2c.  TT measures 53cm c2c, heat tube is 11 cm.

I may put it on here as well if there is some genuine interest.

I知 building my hub into a new rim. Wish me luck!. On the advice of lots of people I知 using a Ryde Andra 30 rim - 700c / 622.

Whose recommendation?  It is the go to for rim braked heavy duty touring use, or in 26" where Rohloff specific drilling is available. But it looked from your other posts that that wasn't the sort of bike you are building. For lighter touring use (But still touring) SJS/Thorn usually use the DT Swiss TK 540, which would probably be my choice. It's not a huge deal, the 700c Rohloff on my Mercury is on a heavy Sputnik rim, because the wheel pre-dates the bike, and though it wouldn't be my choice for this bike I'd rather put up with it than disturb the wheel. 
For spoke length, there's no substitute  for measuring the ERD of the rim yourself, even SJS's website has got it wrong in the past, I know that adds a second postage fee, but it's a lot cheaper than getting it wrong.
I built one of my Rohloff wheels myself, but only because the wheelbuilders I'd trust were closed for Covid.  I've built a few other wheels but the value of a Rohloff I'd rather leave to an expert.  I was lucky as I already had an SJS wheel and simply copied that. There's a thread somewhere on here explaining why SJS choose to build 1X, rather than the handbook recommended 2X, though of course deviation from the Rohloff instructions on your own build may impact the warranty.

SJS has built up lots of Rohloff wheels with Andra 30 rims, ask them.  It is my recollection that they deviated slightly from the Rohloff suggestion for spoke length.  I do not recall what nipple lengths they use, but it might be an extra long one.  I used normal Sapim nipples, and they do not stick out of the rim very far.

I used the table provided by Rohloff for spoke length using the ERD from SJS website for the Andra 30 rims when I built my wheels.

When I bought my Andra 30 rims from SJS a decade ago, I wanted one rim with normal drilling (front wheel) and one with Rohloff drilling.  When I received the rims, one rim had a tag on it with a hand written "Rohloff".

There are several online calculators for spoke length. You would need to input certain measurements. I think, however, that SJS have built up so many wheels with Andra 30 rims that an email to them will answer your question, especially if you are buying the spokes from them.
Good luck

I use an" impact wrench" style method for removing the sprocket. That is, once the chain whip and wrench are set up opposite to each other I lift the wheel about 6 inches off the ground and drop it and push down on the wrenches at the same time.  This usually gives enough shock load that it really doesn't take much effort to break the sprocket free. It can pretty much be removed by hand after that, so, like mickeg, I just lay the wheel flat on the ground, sprocket up. That way there is almost no oil loss.