I’ve used Mo-clean and recommend him. Used to be in Acton St near Kings X but is now mobile. Nice bloke but not cheap. You might have to stretch the £20 kitty a bit
The kitty is sadly depleted. SWMBO has declared that there are no further funds for the bike. So it looks like I’ll have to use a local car wash after all. Such is life. But it is only a 19 year old “classic” and I’m going to fix it up as a winter hack/all round commuter.