Got a call back from plumber. To replace the control valve is about £230, plus labour. Ok So I asked since only a few months ago I replaced the other big valve in the boiler at well over £250 . If I replace this one what other expensive item is likely to go. Thats a good question anything could go Thats the nature of things. Ok give me a price to replace the boiler. So I got a price of between £1300 and £1800 plus TRV`s . So I said OK go for the £1800 which was top of the range, For a difference of £400 quid Its not worth skimping. Because the first call out could cost me that. So now we have agreed a price and set a date for 4 July. He could do it this week but we are not available. Its best to get it sorted during the summer when we dont need heating.