How can I access caravan tap washers?

I have an old caravan with the brown plastic mixer taps. All has been fine until one of the taps started making a noise after use. My pet caravan engineer told me that perhaps the washer has got some dirt in and may need replacing. To save money I am trying to do the job myself. I have removed the tap but cannot dismantle it any further. The micro switch wires are still attached as I cannot see how to get to them. Any replies would be very helpful