Thanks all for your responses. I had indeed misread the info on the Guernsey page on the NATS website.
I note A319 rather than B737. I recall seeing a video of an A319 landing at Vagar in the Faroes, and landing/take-off well within their 4000ft or so.
Equally I suppose as with any aircraft, fuel and pax make a difference!
Thanks again.
EGCA