I've just had a new combi boiler fitted to replace an ageing condensing one, and now our Mira 88 shower temp isn't hot enough when it's turned up full welly (the water pressure coming out of the shower head has increased significantly). Can anyone tell me if it's possible to adjust the temperature of this model of mixer shower? I've pulled off the temp control and C-clip, but the water on-off control dial won't come off. Is there a temp adjuster under this control dial?