Hi thanks to both for your advice. I do check all radiators for air and the only place it seems to arise sometimes is in the towel rail and i bleed that. The pump seems to be a standard size and is running on 2 as advised to be standard setting . I have however run it at 3 for a couple of days and there is no difference .

Nestork Not sure what a gate valve is but i do have automatic rad valves on all radiators .Upstairs are on 3 downstairs 6 (valves are 1-6) this makes most downstairs hotter than hand heat but nowhere near the heat of the boiler outlet. I have checked that none of the rad valves are malfunctioning ie locked down but the water getting there is simply luke warm .

Could it be the pump does not circultate the hot water long enough as the pump runs only as long as the boilers on ? Please if you have any further options i'm just lost .