The help and tips has been great, looking at your pointers tips etc, has lead me to conclude (if I can find one), the Ribcraft 4.8 preferably with a 4 stroke 50 to 60 HP Yam or Honda (Mariner or Mercury, may have to be a compromise), it is the compromise RIB I am looking for.
I would not rule out a Tornado 4.8 but they are too rare.
As seaworthy and rugged Seariders are Montu, confirmed what I had noticed (they have a low bow and prone to get a soaking, I'm ok but my passengers may not appreciate it so much). The smallest worthy Humber Destroyer comes in at 5M, as good though they are, trying to avoid 5M.
As for other RIB Manufacturers e.g. Buffalo, Vanguard Valiant, Ribeye, Zodiac, Ocean, X-Pro, Quicksilver, Lomac & countless others. I have discounted these, on the basis of, I do not know much about them, so I have used a simple philosophy - if the Navy, RNLI or clubs etc use them, then they qualify for me to consider.
So I am on the look out for a suitable Ribcraft - sorry Ribcraft4.8, you are over on the lovely Emerald Isle, far too far and logistically too difficult. As for budget, it looks like I will have to sell my motor cruiser first, to release the money - I will have a hell of a job convincing my other half to part with the kind of money to get a reasonable RIB.
Red Fox, when I can, I will use your tip too, concerning the dealers.
So that is my conclusion but other feedback is still ok, as they say, my mind can change with the facts.