Mild heating and and hot water is luke warm?

Hi my radiators are never roasting and water is not hot enough for a bath or a long shower? My house is quite cold and need this fixed ASAP - can anyone help me? The setting on the boiler mate is at the winter setting and my boiler is a suprima and is at max at all times and I have been told by Scottish power that this is working properly and think its the cylinder itself that is not working also the cylinder is not as warm as it used to be. I know people on here have said about filling up the boiler or replacing he thermostat - is this the problem I have? Also have the buzzing noise but that doesn't bother me- would just like to be warm and have hot water again.

Ist check that the unit is full.
Drain some out and make sure you hear the F&E tank fill.
Check that the boiler pump is running at the BM II
Have you read the posts on the Boilermate II ?
All has been covered before.
Mike
MGC/H2O
Norfolk