Right, I've got an '89 1.3 Popular, 33k on the clock but recently developed some niggly issues!

Firstly, rear heated window doesn't work, is there a typical fault with these?

I've also got a running problem, it seems to be when it the weather cools down towards winter, last year it was an idle problem, gave it a service and changed the leads, 3 sets of plugs, every time I put a new set in, it 'cured' the problem for a few weeks, then it'd come back.
That's been fine since last winter, although we now have a very hesitant car. It'll rev freely sat still but under load it bogs down and struggles to get up to speed, which in a car with less HP than the horses in the field behind us, isn't ideal

I've put it down to fuelling, wondering whether it's crap in the carb, is it worth getting a service kit for it?
It's a Weber, not the shitty VV.

Any thoughts appreciated.

Ben.