Re: Hyper Beluga
"The fly in the ointment is Broughton where the runway is bounded by a main road at one end and a railway at the other. It's also quite narrow."
It's entirely possible to have a runway with a railway crossing. Broughton isn't exactly busy and trains don't run every 5 minutes on that line.
Yes, I've landed and taken off from there.
As for width: It's wide enough to do the job - and it can be widened.