Rear Wiper Lost It's Park

Just doing some niggles (again :-)) on the G and thought I'd ask the collective for advice.

The rear wash wipe has lost it's intermittent and park. I think it's at the motor end. My understanding is there is a gap which interrupts the constant live causing it to park, and I guess this also has something to do with allowing the intermittent feature to work. I know these are prone to filling in (well on the more used front wiper motors they are)..

Am I on the right track? I dismantled the wiper motor once, but I was in a rush, and could not see an obvious way to get to the right bit before I needed to get it back together. So again can you actually dismantle it to get to the part I need to clean?

Or am I looking at the wrong thing entirely and need to change the dash switch or relay?

Any advice before I take the motor off again (by the way first time round it looked factory new - obviously that was the first time it had seen the light of day since leaving Graz - so that sort of made me wonder about the 'gap' filling in) Oh and it does still work, just operates continuously.

Ta

Simon