2006 ETON Bathroom mixer tap not working

I have a 2006 Eton and the bathroom sink mixer tap is not working.  I have dismantled it above the sink and cannot see anything obviously wrong. The reference label on the tap is 09TWC06. Local repairers are wanting £70 just to look at it, so if possible, I want to fix it myself.  I was wondering whether the fault could be a micro-switch as the other taps in the vehicle operate ok. Can anyone here help me please. Is there a micro switch? if yes, where is it located?  Can I source a replacement other than from AS? How is it replaced? In fact I would be grateful for any information at all. So a big thank you in anticipation that someone might have some answers that they are willing to share.

PS if you live in the vicinity of Driffield, Bridlington or Beverley and you know of a good motorhome repairer I would be delighted to have their contact details, just in case. I have resolved the mechanical servicing etc but getting internal jobs done is proving to be a pain.

Hi Mike
Don't know if you've tried Olearys Mike, www.olearysmotorhomes.co.uk   01482 868632, haven't used them may self .We have Springfields motorhome here in Bridington, I cannot comment on there workmanship, these days, as the service manager and engineers have not returned since lockdown.
Unfortunately several MH/caravan mobile engineers went to the wall during the last year.
Boaby

I think the tap is a Whale, have a chat with them to see if they have a local supplier or will supply direct. Normally very helpfull company

If you have opened the upper part of the tap, you  are probably going to find a removable "cassette"  They sometimes develop a leak and sometimes get bunged up.
Not sure if they all have this feature but worth a look.  Replacements are usually available.
Keith

The taps may or may not have microswitches. With the other taps can you hear the pump start and stop. If they don't have built in switches then true pump so be switched off by a pressure switch fairly close to where the water pipe from the tank enters the van or maybe built into the pump if it is a Flojet or Shurflo. With a pressure switch there will be a very slight delay between closing the tap and the pump stopping, more noticeable on hot than cold. If the taps have individual microswitches they will need wires as well as a water supply and you should be able to see those, if present.
Once you have discovered that we can help further.

Thanks for all helpful constructive comments. So I replaced the cassette - did you know 35mm cassette sold by Screwfix for £4.73 fits perfectly? But that didn't solve the problem. What did was removing and cleaning the filter in the end of the tap. Now why didn't I think of that?