I am not familiar with Morrisons, but I am familiar with Peter Lugers. There, the simply offer the mac daddy of all Porter houses. You simply state, "Steak for [insert #] medium rare", and out it comes, sizzling and cut, then served family style.
If it is more a places like Ruth's Chris(over rated, imo), be prepared to pay upwards of $30, per cut, per person...and that is just for the steak, no sides. Sides are a la cart.
I prefer a rib eye or porter, SO prefers, sirloin, or fillet...A steak to suite a whole families tastes might be a tough order, depends on the personal tastes.