I finally took my B5 out of storage and even managed to kick-start her into lifewith my still mending leg. The front brake was sticking on so I spent the afternoon stripping the calliper down, cleaning the pins and slides before reassembly. The pistons have no corrosion on them at all which is a surprise considering I rode through salt encrusted roads during winter for a couple of years. I did find that the holes the pad retaining pins go through were different diameters no wonder it was difficult to remove one of them. I have found this issue before on some Japanese machinery. I used a 6mm drill to clear the holes and open up the narrow one to the correct size.
On reassembly all went together easily and the brake no longer binds.
I also re-torqued the swing-arm pivot bolt (the reason the bike was laid up as the original snapped) to 50lb/ft.
Apart from a good clean the bike seems good to go, just need to get her through the annual ministry of transport test(MOT) and buy vehicle tax before I can ride her on the road again.