Hi 

My mk4 Focus has just entered limp mode with an apparent powertrain malfunction. It's currently parked up at the train station carpark but I'm going to have to drive it home tonight. I don't really fancy driving along a motorway in limp mode, so is there an easy way to reset the fault (assuming it was just a passing "glitch"), maybe pulling a particular fuse or something?

If you want to claim under warranty I wouldn’t. The car is trying to protect itself, even if it’s erroneous. You risk doing more damage and Ford may then not pay out if you’ve tried to bypass it. 
 

Have you got the free Ford breakdown?

Luckily when I got back to my car, it was no longer in limp / reduced power mode and so I was able to drive it home but the engine malfunction light is lit and fordpass is reporting that the turbocharger is producing less boost than expected. I've booked the car in with the dealer as it's still (just about) under warranty but am not impressed as this will be the 5th time it's gone back in under 3 years!

Having taken my car to the dealer they more-or-less said "since it's under warranty it's easier if we just replace the turbocharger" which they did. So I've got a new turbocharger and a feeling that I should take out the extended warranty when this one expires! On the theme of what to do when my current warranty expires - I've also looked into the possibility of trading my car in for a newer, similar spec'd one but couldn't find any on the Ford website - the newest one they had was only 5 months younger than mine and was also about £3000 more expensive than the price I paid for mine 2 and a bit years ago!