I am going to restore my parents' HMV TV. It is still in showroom condition but has been in storage for decades. I have a photocopy of the circuit but it is poor quality. I need tips re restoration, schematics and parts suppliers. Its' valve complement is:
6BY7, 6EJ7(2), 6DX8, 23HP4, 6DX8, 6CS6, 6U8, 6BX6, 6BM8, 6CM5, 6ES8, 6HG8

It's good that you want to restore your parents old HMV. It should perform well after some attention.

What is your level of electronics experience? This will determine how technical I can be with my explanations! Also TV repair is not really for beginners but with some guidance it is not impossible.

From your valve line up, it sounds like you have a PL or PM chassis set. On the chassis of the TV usually around the top right corner it should be stamped in ink with the model number of the TV. It will start with P and will be in the form of two letters followed by a dash then two more letters or numbers. If you let us know the exact model I can supply a circuit for you.

Circuits for the TV will not be a problem. Parts are more of a problem. Some parts are very hard to find now but chances are good you will not need the rare parts. Resistors and capacitors are still available new from various parts suppliers. HMV's from the mid 1960's were using good quality parts so unlike an earlier set from the 1950's, most of the components will be ok still.