Well, that was fun! I took the rigid forks off and found that the bike had been built up with a standard fork crown rather than the split one FSA are supposed to use. Didn't fancy taking it off so ordered another (not from SJS, they don't list them), when this arived it was also the standard type so had to carefully fit it with a hammer & screwdriver!
I used a Gusset Headlock rather than a star-fangled nut and didn't need to cut the steerer, a extra 5mm spacer took care of the excess.
Tightened everything up and it felt OK. Put the brakes back on and switched the pads, I then had the mildly horrible task of adjusting everything. I can only guess that the bosses on the Maguras are slightly further apart than those on the rigid forks. If I make a habit of swapping I'll take Adrians advice and get a 2nd set of brakes.
More than enough cable but my noodle seems to be leaning forward :-)
Short test ride over the local cobbles & potholes seemed OK.
Anyone else done this or have any other comments on the Maguras?