Hot water in bathroom question

[Systemfix]

Hey guys,
I have a real annoying problem that I have a bathroom which provides full hot water to the basin and luke warm water tot the shower and bath hot tap?? this is baffeling as I cant understand why and how this can be possible, what do you think I should check and how may I overcome this problem?
thanks for your help, much appreciated !

 

[kevplumb]

take the bath panel off and have a look under first

 

[Prof.plumb]

have you got a combi boiler

 

[plumbnuts]

You may have unbalanced supplies ie hot from a cylinder and cold from the mains. This would cause a problem in he shower and bath filler if it is a mixer tap but not in the basin taps if they separate taps.