The faster payment is secure and none returnable, so if someone pays you say £15k electronically within 2hours (normally minuets) it is cleared and in your account. This can not be later taken back out by the original payer or declined by the banks so totally safe.
However each bank in the scheme ( not all) has different levels by which they will allow transactions to take place! Barclay is £99,999, Lloyd's is £25,000 but nat west is only £10,000 so best check the the buyers bank. If their bank is not in then system then CHAPs payment in a branch is secure, but costs about £25 to do.
