Well I've upper my budget and purchase a Marconi TF2008, it arrives at the weekend.
It looks in good nick but I won't know until I receive it.
I guess I'll have to open it up and check Caps, etc before powering it on an testing it.
Fingers crossed I got a good one!
Thanks for all the help and advice - I'll be keeping the HP function generator.
Does anyone have any BNC DC blockers spare?