I have the underslung type of manual plunger - it was attached to a smal bracket beneath the dashboard.
I was able to buy, from a well respected classic car parts and accessories dealer based on the Worcestershire/Herefordshire border, a high quality (10mm diameter, IIRC) metal push-to-make switch. This fitted exactly in the bracket, and is wholly unobtrusive.
To power the washers, I fitted an inline pump from my local motor factor (don't try Halfords, they had nothing suitable). You can get pumps with brackets already fitted for affixing to the inner wing, which is what I did.
Looks lovely, and works a treat!
