Mixer shower calibration

Can anyone help? We have what I think is a Bristan mixer 'victorian' shower, with a separate on/off lever and a tap for changing the temperature. There is a pump attached to the system to increase the amount of hot water.

This shower used to work fine, but we've just had some builders in to tile the bathroom and took the shower off the wall. It's now back on the wall, but even on fully hot setting (fully anticlockwise), at best it's now only giving luke warm water. I have searched the internet for manufacturers instructions on how to calibrate the shower, but can only find instructions for showers with an override button, but we don't have one of these.

I've accidently found the retaining grub screw that keeps the temperature control tap in (by removing the grub screw then seeing the tap shoot out followed by a lot of water - I had to turn of the mains water and wait for the tank to empty before being able to put the tap back in! I now know how to clear cold water airlocks too!)

Any advice on how to recalibrate and get a warm shower would be gratefully received

It would be an odd valve that needed calibrating, except for the 'safety stop' position.

It's more likely than you have one of the following:

1. Wrongly assembled controls.
2. Debris in the inlet filter or check valve.
2. Reversed cold/hot supplies.

You should be able to get a drawing from Bristan if you telephone them - it's a big company with a lot of resources. Also instructions.

A pic might help understand the type of fitting you're working with

And if nothing esle - it will likely increase views of your thread, with the intent of increasing the chances of an expert wandering through