Well that's what I'm afraid of. As I mentioned I can't afford to throw £50 on one lesson to find the guy is no good, £40 at a different guy who's no good either, etc.
In my usual four ball only one of the guys has had lessons and he still plays off 30, hasn't really seen what I would call dramatic improvement and I didn't like the sound of the guy he used from what he described. I suppose the other issue for me is not being able to drive so I'd have to pick a location I can get myself to anyway. Probably narrows the options a tad.
Sometimes in life you have to take risks.
Also, you see lots of guys take lessons and expect the pro to work miracles in that lesson without them working on what is taught, sometime you only get out what you put in.