I took one of my Marshall's to Bletchley HQ 10+ years ago and they didn't change the Bulgin plug on it. I would suggest that you take it to Marshall (being so close) to obtain an appraisal of the amp of what they think needs doing and the cost. You will have a better idea then for your next step. New reissues of the amp are around £1300 so I guess the amp is maybe £3k depending on its originality/ work required and of course what someone would pay for it.
The OT must have been installed before mid-late 70's .... as that was when I bought it - and no work done on it since thenThose fuse holders only seem to be around 68-69, coincide with the brown paxolin selectors. I have never seen any for sale elsewhere or on any other amps. It was one of those I had to repair on my 68 JMP 50 as there was corrosion and intermittent contact on the HT and hard to track crackle.
The rectifier mods are pretty obvious (these had the flying diodes, post tube rectifier era and pre rectifier block era).
Toro tots are almost impossible to find too although I have some that look the same externally (short round black bat type). Regarding v1 plate resistors you do see those now and again (and on v2 socket). They are RS branded 10% and that plus a bit of drift to 120k or so can actually give v1 a bit more perceived gain. Other places you see that type of resistor is tone stack 56k on bass amps and 470k mixers.
Wonder when the OT was replaced. Looks a bit like a Partridge or the EV brand and appears to have been there for a while.
Where did you see those pics!!!
Yes def Partridge
looks like TG9624?
Do you know where they were used Stu? Not one I recognise.
Does anyone know the date code system for Partridge transformers?