Having spent a lot time in rib in the med. and other temperate locations for work and for leisure. In the UK, you will not see a more utilitarian type boat than in any other region for a reason and a majority are that way. As ribs in the Uk are excellent boats and very sea worthy, they are not necessarily the best boat in the med for family and leisure. Not saying you couldn't do it.
Based on my experience I highly recommend looking for a rib that will allow you quality time and comfort while at anchor and at speed. Having a foredeck that will allow you to lay down or give you the ability to sit down comfortably with a friend or friends for a lunch. Also, a place for a ice box to keep drinks & food cool is important in the med.
Having jockey seats are pure joy for your back while at sea, I love them for that while working but fairly sure you won't always need them for everybody in the med for leisure use in good weather. You say two people mostly and maybe four occasionally. I would think having two jockey seats at the console and a bench seat in the back for the occasional passenger and storage. It's easy to remove jockeys and put in a rear bench seat/locker if you like. You can alway go back to more jockey's like the rib in the pic.
Having said that, you also need to be careful of the type of weekend excursion med ribs with all the bells and whistles with fancy lines, they are not known for the best quality, reliability or sea worthiness. I say to try to find something in-between.
I like the layout of this rib in the pic (Ballistic 650), it has the ability to convert the bow into a big sun bed or four people or more people sitting comfortably during a sunset cocktail.
There's nothing better than speeding off to a remote quiet cove, setting a anchor for a nice lunch, take a nap or read a book or all of above. Your wife, girlfriend or mistress will appreciate that.
I'm not sure about the quality of Ballistic ribs or this one in particular, others on the forum will be better for that. It's for sale on rib.net (2007 Ballistic 650 - 175hp £18,000
). I think this could suit you well and appears to have a fairly good v hull and bow looks like it's high enough for sea worthiness in the UK.
Fancy med boats will not do in the UK so I recommend finding something (if possible in budget) that can suit both regions. I think this type of rib layout can offer you that.