Steve,
We have turned full circle on this Steve, you are now the expert on Lucas mirrors as I havent attempted to take the ball out yet, Jays stem will arrive soon.
My current plan will be to use a small butane torch (used for soldering) to heat the top two tabs and then let them cool slowly in air, thus anneling them to make them 'softer' then attempt to bend them back and remove the plate, once the plate is removed, re-anneal the two pins, fit the new ball and bend them back.
I know that there must be a few people here who have already done this so I guess we both wait for them to speak up or you could bite the bullet and go for it..... I will be asking questions if you do it.
Kim, sorry found the Lucas 608 and couldnt resist a bid myself!!!!!!!!
Andy