Is it possible (it used to be in older cars I used to own) to change the rear-window wiper-relais to an interval relais? The rear wiper is pretty useless wiping all the time (it only starts squeeking really fast).

And if so, which editions have an interval on the back?

my sporting has interval one, i dont know if its controled by the relay or body computer though, could see if they have diffrent part numbers on eper if its working today

eper not much good, all it said is
2 RELAY
46520411 20A 01
46520412 30A 02
46520419 50A 01
dont say what does what

Sorry to hijack but i would like todo this, Do you reckon it is easy todo? and what about installing variable speed intermittent wipers on the front ?(i think the top model mk2b punto has them)

I guess that the variable interval is changed / switched by the computer; I hope the punto's on-off interval isn't but by relais. On the other hand, if it is switched in the computer it might be able to switch it on or off by OBD.