In the UK the domestic supply is 240 V AC, commonly provided from transformers that deliver 415 V phase to phase, 240 V phase to neutral. This allows bigger light industrial loads such as three phase motors in farms or factories to run off a 415 V three phase supply.
When someone talks about 230 V three phase, they likely mean 230 V phase to phase, rather than 400 V phase to phase.
I believe the domestic supply in the UK used to be 240V but now is 230 V RMS +10% -6% and has been so for quite a few many years now when it was changed also in the continent from 220 to 230 so now it is 230 V all around
Old people in Spain still say "220" but that is just a manner of speaking and it is no longer 220 but 230. In the UK as well.
So it seems we have the same delivery system. 230V phase voltage. 230 V between phase and neutral. With star configuration so neutral.
When someone says "230 V" they most often mean phase voltage and if they mean anything else they are leading to confusion. If it needs clarification they might say "230 phase voltage" or, in industrial settings with 400V motors they might say "400 V line voltage" or "230/400" but this never comes up in residential settings.
At any rate, I confirm residential supply in UK is exactly the same as it is in Spain: 230 V phase and neutral.
Exceptionally in Spain there might still be rural areas with decades-old transformers which might supply 130/230 but they disappear as they are being replaced.