I went back to basics, assuming that not a lot could be wrong as it had passed it's MOT 2 weeks ago & they were bound to have checked the washers worked

The guy I got it off had been playing at fitting radios, speakers, etc, so I had a brainwave... fuses! Yes, both the washer motor & the washer switch had blown (along with another 2), so replaced those, switched on & fingers crossed ... nothing

Checked fuses again, but both looked OK, so being a suspicious type I swapped another 10A fuse from another fuse slot into the motor slot & it worked! ... well sort of.. a tiny dribble not the Niagra I hoped for. Inspected replacement fuse I pulled & it looked fine, no breaks, etc, but just didn't work.
With a bit of fettling ( a good tip is you can get a "boilie drill" for a quid or two from your local fishing shop which makes the best wiper jet cleaner ever, I always keep one in my spares kit) Typical of my luck I managed to get a really good flow from passenger side, where I don't need it & dribble from the other, so it looks like new jets & a good clean out is in order. The water must have been overflowing rather than leaking I think.
I'm off later to the local Peugeot dealer to get some Pug 607 jets, as I read on here they are a push in replacement for £4 a pair ... unless anyone has any better ideas?
Then all that's left is to work out why the analogue dash clock & ciggy lighter are not working, but the radio is, fit a mains inlet, consumer unit & power points / lights, investigate the slight oil & water drips under the engine, re-trim the interior & refurbish the cupboards, start on the rust..... and maybe if I get a chance even use it as a camper sometime

Thanks for all your help & advice,
Steve