IIRC the 550 was wider than other Trolls right from the start and the others came into line with it widthways when the height etc was altered in 2010. I think I'm right in saying the 550 was always 6ft 6ins across (2m), whereas the others were 6ft 2ins 'til 2009.

The 540 'langslapper' has 6ft5ins to 6ft 7ins long single beds (depending where you measure) and was 6ft 2ins across 'til the changes in 2010 made it 6ft 6ins.

Just for clarity, I'm quoting internal measurements and Colin's quoting external. The 0.1m, roughly 4ins, difference is the depth of the walls, with insulation.

The wheel spats on the 550 Troll have to be fitted facing the wrong direction as the position of the toilet cassette door would interfere with the spats greater bulk on the 'back end' if it was fitted the 'correct' way around ...if that makes sense.

I was originally shopping for a 550 but ended up buying a 540. This was mainly because a really nice 540 came up for sale but now that I have it there are a few things that I really like.

I like the large rear dinette and when it's made up into a bed I like the view from the three large windows, especially in the morning when I'm having a cup of tea in bed.

The option of having 2 long single beds is good when camping with people you don't want to sleep with (friends, children etc)

The front dinette is undeniably snug but it's a lovely place to sit and read the paper and have coffee while your other half has a lie in. The bay windows provide a lovely view and the wide window ledge is really useful.

When I was buying the Eriba I thought it was because I love outdoor activities. I'm now realizing that I also love outdoor inactivity and the 540's sofas are long enough to have a really good post-lunch nap.

Last weekend my 15 year old son came to the New Forest with us. Once his bed was made up at the front he had a lot of privacy because the kitchen and the washroom divide the van from front to back creating 2 distinct areas. We all appreciated this.

The 540 (2006 vintage) is 10cm narrower than the 550 which makes it easier to tow as it's exactly the same width as my car. This also means I get an excellent view without towing mirrors (controversial, I know).

Oh, and the wheel spats are the right way round.

Of course, the 550 has loads of advantages as well - mainly around roominess - and if I was buying new I'm really not sure which one I'd go for. I'm sure I'd be happy with either but these are some of my observations based on 3 fantastic weekends away in my 540.

Absolutely spot on!
The 540 is the perfect portable ‘cottage in the country’.
TonyP