Site has lost stylesheet, links point to dierent domain

Hi folks,

I’ve recently has a few problems with my domain. The link to my stylesheet is wrong.

https://www.walsallccg.nhs.uk.smart-hosting.co.uk/

Is there a way I can change the base URL without logging into the website?

I can’t login to wp-admin I get a HTTP error 400 bad request The request hostname is invalid.

Manhy thanks