Hi Al,
Sorry to wade in (first post on here as not in aviation professionally - my extra-tenuous link is that I used to be an Air Cadet at Brawdy in the late 80s/early 90s so may have flown in your SK some time
).
I've certainly seen SKs land at Withybush since the new A+E building, I have a pic somewhere of TWO on the gound: one on the pad and one in the staff car park, from a couple of years back, looked like the first was having technical difficulties.
I could offer two guesses as to why thy aren't using the pad at the mo:
1- It could be fire appliance cover - I understand the access/pump fire appliance at Haverfordwest that used to attend any SK landing has been temporarily assigned elsewhere and only a conventional pump appliance or a Sprinter van-based unit is available. The latter a product of yet more public sector cutbacks! Withybush 'Airport' has it's own 4x4 heavy crash tender, but not sure of out of hours availability etc.
2 - Could be due to the building works for the Renal unit, with plant trundling about the site a lot at the mo. Might be way off on both counts however
As for Glan Gwilli having a heli pad, using a very unscientific approach and looking on the (admittedly dated) Google satellite imagery it appears to be a no. Losing parking space might be a difficulty to make one, as there isn't much of that either.
As a local to Hwest, with two kids, it's all very concerning to say the least.