I'm moving continents, far too many developer tanks.
I'd guess 50 or 60 possibly more.
A lot of early Paterson tanks, but mostly I think Series 3, they are excellent for E6 as they are smaller than more modern tanks and use far less chemistry. I used them in E3/4 days.
Free you pay shipping/postage.
I'm giving away free or I'd post on the classified.
My friend has been on a couple of episodes of 'Tank Overhaul'. In the eposode I have seen he has two damaged Sherman tanks. One damaged at the back, the other at the front. He cut them in half (1.5" thick steel) and welded them together (he is a specialist welder by profession).
He also has a Comet so it may have been him you saw.
Back on course now. If you have any old tanks of historic interest, the photographic museum at Dimbola Lodge, the home of Julia Margeret Cameron, here on the Isle of Wight may be interested.