Which Regulators?
Like everything else in diving, choosing a set of regulators is a matter of “horses for courses”.
Are you only going to dive abroad? In which case weight and compactness are the key. A mixture of UK summer diving and abroad could be serviced by the same set of “regs”, but if you are going to be a hardened UK diver, diving year round, then you will need an environmentally sealed first stage matched to cold water rated second stages.
When choosing your regulator, think comfort too: some regulators are featherweights, others are the “Mike Tsyon’s” fo the diving world, real quality heavy weights. Jaw fatigue is a very real fact of life, not just for gossips!
If you go down the technical diving route, you will end up with multiple sets of regulators (but do remember, they all have to be serviced every year!).