If you're looking for good deals check out www.redfunnel.co.uk/camping they have good deals for campers. 5 nights return ferry crossing for £117 out of season (when the kids are in school). I am sure some of you will think it's expensive but I think it's good value and good campsites too.
it's the most expensive ferry crossing mile for mile anywhere in the world! book for a night crossing, turn up at what ever time you like, and usually they'll put you on the next boat with space! only once was i turned away at 930pm the boat was half empty and i was told i'd have to wait for the midnight crossing, but half an hour later the shift changed and the next bloke said i could go on, and called the other bloke a tosser!
Why would there be a difference between high top and pop top? space should be calculated on length and width of vehicle. When i sail with caledonian macbrane all they ask is length of van and whether you have a trailer.
Other half's family live their (we did too, but we escaped!!). We are members of the comping and caravanning club purely for the reason that the membership easily pays for itself in the cheaper ferry fares. We have just been over - Wightlink - for a week £60 inc the £5 fuel surcharge ther are putting on. If you are using the deals which are crossing time specific it is worth going Lymington - Yarmouth - they often let you board early. We found Portsmouth very tight on this.