I hope she does consider ERF, and that she can get info from AD (AdventureDad) or others about the Swedish RF seats (check out carseat.se for more info and seat options). AD can speak very well to how easily a seat installs.
Aside from the Swedish HWRF seats, I had looked at buying an EU seat when I was visiting family in 2009 and looked at a number of seats. I am almost sure at least one was able to install with a 2pt belt (lapbelt only) if that is a benefit to her, but I can't remember which.
I considered the Britax First Class. It RF to 13kg (28.6lbs) and then FF to 18kg (39.6lbs), has lockoffs (at least for the FF install), and 2 routing options for FF if the first method doesn't work. It seems to be fairly straight-forward to install and doesn't have a foot prop etc that might be incompatible with a vehicle. 3pt belt only to install:
http://www.britax.co.uk/car-seats/car-seats/first-class-plus
I had also considered the Concord Ultimax, very similar in limits (also 13kg RF and 18kg FF) and features (lockoffs) to the First Class, it seemed. It also has a base, of sorts, to make it easier to install - see the 3rd picture in the link:
http://www.toysrus.co.uk/Babies-R-U...-1/Concord-Ultimax-Car-Seat-in-Chilli(0069590)
And then, the Bebe Confort Iseos Neo+ (not the TT or IsoFix, they are FF only), and it seems like they have a new one, the Opal (page 29) that is better for ERF. Bebe Confort seems to have some overlap with MaxiCosi. For the Opal, they say "
this car seat can be used for an extended period to protect your child up to the age of around four years. There’s extended leg room and an adjustable headrest so the seat can be used in its safest ‘rearward’ position for a longer period. You can easily change it to a forward-facing position so they can see the more of the world around them, when they are old enough." while the Neo+ seems to focus on it being for small kids (p.31). Opal is also 13kg RF and 19kg FF:
http://www.bebeconfort.com/collection/catalogue/catalogue-bbc-uk.pdf
or
More info on Opal:
- Easy to use: with a click, the seat can change to face towards the gears and the safety belt can still pass through the same point.
Same lockoff works both RF and FF, non-rethread harness.
see the details here:
http://www.ebaby.co.uk/bebe-confort-1/opal-car-seat-bebe-confort.html