@lukisrAre the text's coming from a number that begins +447802 by any chance?
It is usually down to the host network from your contact supressing Caller ID or it been corrupt when sent across to the UK.
I have seen this especially from colleagues in Manila texting me.
The only think i can think of is ask your contact to contact their network provider.
Also is your phone a personal or work phone? As some work phones are on a system called Mobex which causes issues with international services.
--
iPhone 16 Pro Max - o2 and Spusu
Xperia 1V - Spusu
--
This is not customer services and we dont have access to your account
I do not work for o2 or any VMo2 /Telefonica/Liberty Global Company