If something is too good to be true, it usually is.
In all seriousness, going with a reputable shop (Adafruit, Sparkfun, Pololu) can save you a bit of headaches later, especially if you are doing integration. You might ask (email) the Pi Hut folks why you should buy from their place, rather than the other place, I'm curious what they would say. I don't think this needs to be an accusatory sort of email (how dare you charge more!), but more of a "I see there is a price difference; obviously, something is going on which I don't know about, can you explain this?"
I've bought cheap stuff from Amazon (Arduino clones), and they'd work... after a fashion. Bad solder masks, badly soldered components; all would make getting things going a real pain. Sometimes, a component (like a voltage regulator) wouldn't work, and so an Arduino clone would work when plugged in to a USB port, but not in a standalone mode. Then again, this was a 4 for $10, vs 1 for $15, so it was a bit of a lark, but there was a build quality
If you are putting a lot of effort into the software for this, or paying someone for the software to be developed, or this experiment will be a costly one, the price difference wouldn't be as much of an issue. Is £90
How many of these are you building, BTW? If you are building many, cheaper components might be an issue.
Someone might have another take here; the other shop might be quite reputable, but you have to ask why there is a huge disparity in costs, yes.
If you are wanting to sell stuff online, people may ask for warranties, or expect something to work for N months/years; what would happen if these units fail?