G,
I had a careful look at the surface finish I had achieved during polishing and there were still some surface imperfections which had not polished out. These were in difficult to get at areas which my polishing mops and I decided that I would not spend more effort trying to get a 'perfect' finish. Because of the brake plate being not perfectly clean, I decided against trying to apply lacquer this time.
I have re-assembled the brake plates with the re-chromed levers and they look pretty good.
CB77 Front Brake by
Gordon McConnell, on Flickr
CB77 Rear Brake Plate by
Gordon McConnell, on Flickr
I noticed that the method of attaching the brake levers is different on the front and rear brake. I dont know whether this normal for the year of manufacture (1964) or a mix of earlier and later parts on the bike.
Anyway, I am pleased with the refurbishing result even if I will have to regularly polish the plates with SolvolAutosol!
Thanks again for your kind advice.