You cannot gain access from the front.
Remove the black cap at the top of the column and look down inside, you will see a laser cut ‘W’ bracket with 4 short screws. Remove the screws and then pull the complete column forward from the top and it will unclip. You can then disconnect the push fit pipes and then remove the column completely. On the back you then disconnect the various pipes and make a note of the current settings on the controls on the front. Then remove the 4 securing screws holding the flow/temp/diverter assembly and pull the complete assembly out. Replace any parts you need to, you may will have difficulty sourcing them!
Reverse the above to reinstall making sure the controls all line up in the same place as when you removed them. You may well find that some of the 10mm push fittings leak when you reinstall it so best to have some spares.
The above is quite complex, take photos as you go along. If you struggle to get hold of the parts you need send me a message as I may be able to help.