So I've not paid this much attention but had today off so revisited it. All the solution had leaked out although the plug was still in the bottom bracket. It has got messy too so left it out in the sun to make sure it was dry & went back to it this afternoon.
I've been using fairly gentle solutions & it shows, minimal removal of material however some has got between the post & frame & loosened the top of the post however the rest is still stuck firm!
I've started so I'll finish, it's all good practice.