Hello again Colin
Thanks very much for the links, I looked at the Weber one when I was considering the Ampeg build. You might want to take a look at the Solsound shop on EBay (hope that this is okay with the moderator, it should hopefully be as it is connected to the discussion...)
https://www.ebay.co.uk/str/solsoundlimited
They do lots of nice bits and I have brought from there several times, I have no connection other than being a happy customer.
Repurposing chassis is a good idea, it would certainly save all the work of bending and drilling.
The Vox sounds like a gem, worth getting back to as near original as possible.
All the best
Alan