Thanks guys, I'm going to get the local bodyshop to fabricate a piece unless the rot is more extensive than we think, in which case Martin Robey sells the half wing panel significantly cheaper than anywhere else I've found (about £200)

Does anybody know if there is a rear wheel arch repair panel available for the classic S Type? I can find the entire lower half rear wing but this is much more metal than I need and it isn't exactly cheap.

OK thanks, I'll give it a go

Found the contents of the brake fluid reservoir on the floor of the garage (flexible hose split and now sorted). What type of brake fluid should I use to top up and bleed the system? Dot 3 or Dot 4. Can anybody help?