Hot water problem

[tcreedy]

Hi
I have a Britony Combi 80. The problem I am having is that the heating seems to be working fine however the water is only coming out lukewarm does anybody have any ideas about what I can do to sort the water out. I have already changed the thermistor.
Thanks in Advance

 

[breezer]

see this

 

[tcreedy]

I have checked out the link and I have given all of the info that I can that is on the link. The only other bits i can think to add are that it happens anytime i turn on the hot water taps and it has been happening for a few weeks now. As I said I have changed the thermistor but that is the only thing I have really tried as I dont know what else to do.
Thanks

 

[boilerbeasty]

Does the hot water temperature vary when you turn the control on the front of the boiler (the one with the tap symbol next to it)?
Mine is set at about '11 o'clock' with it being winter. In the summer its a bit lower, because the incoming water is warmer.