Catching feral cats

We seem to have aquired some kitty visitors! I saw one about a month ago and thought it was odd because it didn't look like the neighbour's cat, and cats rarely venture as far down the lane (long private farm lane - farmhouse is condemned though so they're not farm cats). Over the past week I've seen it again, on a pretty much daily basis, and a second cat, constantly hanging around the garden. Checked with the neighbours and they've said they've had one hanging about at theirs for the last few weeks but their cats must've chased them off.
Ideally I'd like to catch them to have them scanned for microchips to see if they belong to anyone, but they're vary wary of people so thinking they may be feral. If I enter the half of the garden they're in, they'll freeze, then run off if I don't leave/if I move closer. They look like they're young adults rather than kittens though so odd that I've not seen them before. A rescue has offered to neuter them if they are feral, but won't take them in as they're too hard to home (they're full of tamer, more home-able cats as it is)
Any tideas? Printed some "found" posters (with vague descriptions so I can tell if whoever comes forward is genuine) to take to local petshops/vets, going to see if any of them or the local rescues can lend me a/some cat traps, emailed the local Cats Protection branches (we don't have one for this town apparently but nearby towns do so tried several branches) and other local rescues. I've put food and water out (one of them ate a little food, cheeky thing had a nibble on some raw chicken wings I'd left down to defrost too!) and I'm going to clear the dog kennel we have of all the junk stored in it to move into the corner they're hanging around in to shelter them from the wind (open fields mean we get quite a wind building up). I'd like to try to arrange for a rescue/organisation to take them on before I put traps down though as I can't keep them (dogs aren't cat-friendly) and I assume if they're trapped once, they'll be a lot harder to trap a second time.
Any other tips?

Even if the farm is a condemned building you'll still get ferals. Or some ****** has abandoned them we get that a lot here at my farm the sods.

CP should come out with the traps so you dont have to and then they should rehome them to other farms as long as there is a barn for them they'll go to it. If not feral and have lost there way they'll know as if once a pet they'll let a few humans touch them.

I have ferals and semi ferals here and they tolerate the dogs as the dogs them.

good luck.

It's really not like a regular farm, just fields with cows/horses and a falling apart building. We've never ever had feral cats and I've lived here over 20 years so it's odd for these two to appear now! They may have been dumped but it's an odd route, other than my few neighbours, there's no other houses and it's a no access road so not like someone's passed by on the way to dumping their cats and decided that would be a good area.
Vets had a B&W cat reported missing but phoned the owner and it had been found this morning - haven't seen either moggy yet so maybe one found its way home but will keep an eye out.