Blimey.. Sea Viper is a new one on me (and probably an old one for you Skip)
I don't think I ever got to see a T22 although they were in service toward the end of my time. I think I got to see a T23 but some years after I'd left. The T42's had eradicated the Counties although the majority were batch 1/2. Put one of those next to a Leander and they 'looked' considerably bigger though not the size of a County. Being more used to seeing the original T42's.. the batch 3's looked a little odd with their longer bows but as well as being more economic.. I understand the batch 3's were better sea-keepers too.
Dave, the weird thing about the stretched 42s was internally the space seemed to mostly be an empty compartment called the warfare annex! I couldn't understand why they hadn't used it to make the accommodation less cramped. Still at least they were a bit wider too so you could pass people in the 2 deck corridors!