I was slighly wrong, it is the tips and messages that can be displayed in Welsh.
However it is still worth checking your Search Settings are set to English, and that no other search option identifies you as being in Wales.
It also COULD be that the machine was repaired in Wales, and they connected it to a Welsh broadband service to test it, so now the browser, or search engine, thinks you are based in Wales.
Certainly there are some web sites that seem to know where I live (based on my local Broadband supplier I suppose) and offer me local services. Some of the adverts offered are also local to me.