Be careful when using lbc. A few weeks ago, a friend of mine carelessly sold some bitcoin to a high-reputation buyer with hundreds of transactions. Turned out that the buyer had purchased the account. My friend ended up only losing a couple hundred bucks, but it could have been much worse for her. Just make sure that there aren't huge gaps in the buyer's history. I've done over two dozen trades on localbitoins myself, ranging from $50 to $500+ in transaction sizes, and haven't had any problems myself. But better safe than sorry!
Do you know what payment method the buyer used? I'm not 100% certain of this but I don't think a UK national bank transfer can be reversed unless it turns out the buyer has had there bank account hacked. That's very unlikely as they usually have very strong security (mine has a physical 2fa device). I have seen localbitcoins accounts listed for sale but usually US ones and never a UK one.
Ah, sorry, I forgot to include the payment method. It was with PayPal. The buyer apparently used a PayPal account with a credit card that didn't belong to him/her. My friend's account ended up getting locked while it was investigated. The lock was released within 2 days, but the payment that was made by the buyer was removed from her account. I'm not sure of the overall outcome of the situation; whether she filed a report to lbc or not. I can check with her the next time I speak with her, but that's the gist of what happened based on her fb post regarding the matter.