My old Kingfisher RS60 has started to boil the water even with the
boilder thermostat set to the minimum possible.

The wall thermostat works Ok and turns the boiler on and off and also
the ho****er tank thermostat will do the same.

As both the hot water and heating pumps are running OK and the hot
water tank heats the water and the rads get hot I am guessing the
boiler thermostat is shot.

I have the maintainance guide for the boilder which explains how to
change it and lists the Part as either -

Thermostat, Ranco C26 P0610 Potterton Part 404456 British Gas 382
291

or

Thermostat, Ranco C26 Potterton Part 200996

Does the panel think this is the most likely problem ?

If so does anyone know where I can get one ?

Cheers

Steve