As 90% of all broadband is supplied by the big 4 suppliers, it’s reasonable to shop around for a better deal. This can prove troublesome though if you are using your suppliers email services after you move. Some companies are now charging up to £7.50 per month just to keep the address active and ofcom think this is ’daylight robbery’. The BBC has more on this story/
https://www.bbc.co.uk/news/business-51571275