Aqualisa Aquavalve 605 Thermostatic & 405 Manual

First I would stick with your original cartridge sometimes they will work OK with a combi, it may ware out sooner however you could get a couple of years out of it.

If it doesn’t work then you will have to fit a pink cartridge.

The difference between thermostatic and manual is, with a thermostatic valve whatever temperature you set the valve at, the valve will hold the water at that temperature, even if the temperature of the water coming in to the valve changes.

This handle just pulls off or levers of with a couple of screwdrivers between the knob and the temp dial.

They can be very difficult to remove!