Triton T550i Twin Impeller Mixer Shower Pump.
This is much cheaper than elsewhere, a Google shopping search brings it up at about £160 - £180.
Also I believe the 10% off day is on 3rd January so potentially even cheaper.
* A pump designed to convert an existing mixer into a power shower.
* Delivers a high performance - up to 14 litres/min.
* Switched on and off automatically as the shower is operated.
* Variable speed control allows flow rate adjustment.
* Four flexible connectors with 15mm push in fittings.
* 1 year guarantee.
* The price shown includes our latest in store discounts.