Mat
glad that reference helped - and pardon me for not saying congratulations on going solo! It's nice flying without that nagging from the back seat isn't it!
Can't help you on the certificate costs. I know that I didn't actually apply for the A certificate as such, a bit of paper saying that you survived your first solo is pretty meaningless and I didn't apply to the BGA for anything until I passed my Bronze.
But that was a regrettable number of years and about 2500 launches ago and I can't remember whether the BGA charged for both endorsements - I'm sure it wasn't £20 quid back then either!