I suspect is was the same thing I was called out to at the island vets. The staff though they could smell gas but there was no gas leak at the property. Someone from gas board came out and while checking round with his gas detector we lifted a drain cover and realised thats where it was coming from.
The island Indian restaurant also had the same issue that another person was called to who saw us and realised it was the same issue. Checking round all the drains on the whole row seemed to have a fuel vapour type of smell eminating from them.
It was almost 8 by this point and I had to leave to get home but I know fire brigade went out. From what I've been told they left once happy the smell had disappeared and rushed off to wetherspoons. I'm assuming whatever is was had found it's way there.
