Hey! Long time no hear!
The battery thing would indicate that you have something draining your battery... One simple thing to check is that the trunk light is off... just look through the space between the rear seats when the bin is out. Other than that you need to track down the current leak. Maybe the dealer caused it while replacing the light?
I don't know about buffing... post a message in the show and shine section or in the Canada forum. I know that there are members in London.
Richard Paul is still selling the shifters. And the members in London will certainly install it for you.
http://axialflow.com/products.htm - near the bottom of the page.
https://www.rx8club.com/private.php?do=newpm&u=10353 to send a message to Richard
Those tail lights are waaaaayyyy to expensive... and it's Mazda's fault it went bad... Grrrr
You should head out to some local car meets in London and start networking!
What are housing prices like in London?
TTYS