Hot rads?

The c/heating boiler has just had it's annual inspection by British Gas and the engineer checked all rads and turned them to fully on AFTER checking on the timer the heating is set to OFF reason he turned rad TRV valves on as he said they have a habit of sticking during summer if turned fully off.

Problem:- boiler Potterton 16-22 Neataheat Mkll F has normal external timer control shows c/heating off and hot water set to once a day. In the shower room is the airing cupboard housing the hot wate cylinder and the rad in that room next to the cupboard is hot, very hot, so is the bathroom radiator next door to the shower room. We don't have a room stat in the system. Why are these two radiators hot when all the rest are cold?????? Also what's the spares situation with this model which is quite old previous owner had it installed.

We've been here 4yrs now and each time the engineers have serviced it they tell me it's getting difficult to obtain spares so you need a new boiler. As if I've got £4,000 tucked up my sleeve,which was the quote last year from British Gas for a Worcester boiler only, nothing else just a boiler change about one and half to two days work I was told. Being on a pension I can't afford that kind of money and I won't entertain finance you end up paying near double.
Oh! BG's installation package in that figure was £1500 double the cost of the same boiler I priced up on the internet.