01-2456-4751

This appears to be yet another spoofed number, that is, it appears as a legit UK number on caller display but on dialling it back, "The number you have called has not been recognised"
If it's not a legitimate number then it is another scammer of some sort. Now blocked on my BT8500

This is not valid UK number - landlines in UK start 01, 02, 03 & all have 11 digits; mobiles are 07, (excl 070) also with 11 digits; there's a veritable raft of freephone and premium rate but they're 03 or 08 mostly 11 digits, &  lastly 09 (invariably adult content). (Add +44 for international but omitting the first zero)

Hi Robbie,
Thank you very much for that information, as I must admit I never knew nor really paid attention to the number of digits in what I thought was a UK landline number appearing on my Caller Display. I always just tended to look at the 01*** then check the area code.
It's a very helpful tip to know about the 11 digit qualifier.
Thanks.