Sounds like an old school tax dodge.
Not too many bookies go out of business.
Basically what happens there is that some punter or organised syndicate sets themselves up in the corner of the pub.
Bets are placed on impending races/ games/events and depending on the liability of the stakes bets are 'laid off' with a runner to the bookies.
Nowadays, they can just as easily be laid off online in seconds.
I imagine most operate online nowadays.
Such enterprises are usually. .erm, ' organised crime' syndicates. One, because sufficient funds need to be readily available and secondly, because there's no room for sore loser's. Thirdly, because it's illegal.