Hi Richard,
Tried this myself a couple months back and couldn’t get anywhere. Contacted Google rep and he apologised that this was not currently open to us, but said it was something they were looking to expand into.
I was happy to hear his fair answer. But I did make the point that if Google demands relevance for its searchers, then it’s a bit unfair that in our area (I’m sure not the only example) the top result for carpet cleaning services is a Google Gauranteed listing showing a company that is based over 115 miles away! Hardly local relevance. Hopefully they’ll take it on board.