You can't actually speak to an actual person, but you can book your bike in for a "free health check" and they will advise what work needs to be done.
I do that, wrangle bike in boot of car, drive to Halfords (takes twice as long due to diversion), wait for the single member of staff to be available, explain the issue (I don't want a health check, I just want my tubeless tyre fixed but I could see no way to find out whether they could do it and if so, when), and ask if I can leave my bike with them.
Oh, you can't leave it here. Oh, we can't repair tubeless tyres, but I can find somewhere that does (nearest other Halfords is at least 30 min drive away).
Drag bike back down the stairs, and come home.
Fuckers.
Why is their website so vague? If they'd said "we don't fix tubeless", or if their arsing talk to a robot 'ask an expert' was only a little effective it would saved me the whole trip.
nb I do have a usual mechanic, but he's away.
nb I know I should learn to do this myself, but somethings I just like to pay experts to do except there aren't any experts