The VII is no better protected than my 2 yr old VI , but as I don't use mine in the winter or the wet I don't have 2 bother with underseal.
However u do , it is essential 4 a car used all year , the main problem on UK roads is salt. There r lots of overlapped seams on the underside and once salt find's it's nasty way in then the results r inevitable. Also there r a number of areas that r vunerable 2 debris impact from the tyres , so stone chip protection is required there.
My suggestion wud b to find a company that can steam clean and treat under 1 roof , it's pointless 2 underseal without thoroughly removing all traces of salt and dirt first , if salt is sealed in u have a worse problem.
Try locating a company that specialises in treating classic cars , my experience of bodyshops that offer underseal service is not good , all the 1's tried just sprayed wax in the general direction , hopeless.
Even if yr car has only been driven 20 miles on salted roads u will HAVE 2 have it steam cleaned b4 treatment.
Tell them 2 b careful with the brake calipers , and I wud recommend that the AYC (if fitted) pipes etc r sprayed with waxoil only, then cleaned and re-treated every spring , this wud apply 2 suspension arms , diffs etc 2.
