I’ve priced matched in Halfords plenty of times. Depends on staff member so easiest way I have found is see if its in store, then call there customer service number.
Tell their call centre where online its cheaper, they will price match, then tell them what store you want to collect it from and they have it in store because you have just seen it. EVERY time I have done it they have immediately called that store who take a note of the price match price and 5 mins later I walk in and buy it in store!!
Bike bits, kids car seats, camping bits, lots really, just easier to get them locally than internet order (for the same price!!)