New shower needed - help

longwalks1

our mixer shower (has shower pump under the bath) and has 2 turning knobs to control it (1 for heat, 1 for power - they are mounted on the same spindle, 1 'inside' the other if that makes sense) has finally stopped working, and seized up. We need to get it replaced ASAP, the one currently fitted is a Wickes one, possibly 10 years old (was there when we moved in) and i had a look on Wickes website and the general reviews of their showers is, well, rubbish.

What should i be looking for please for a mixer shower that wont play up, and hopefully fit the existing hole (or near enough, as its completely tiled in place)

As still gutted that the new shower pump a plumber fitted was from Wickes, again I've since seen it had awful reviews and is noisier than an airplane taking off :mad::(

Please brighten my day!