Recently signed up. We keep getting calls for someone else.

[#1]

We recently signed up with Plusnet. Everything was installed and works fine, however since day 1 we have been receiving calls for a Mr and Mrs Brennan from various call centres.
Presumably this is who had this phone number before us.
Any way we can make this stop? It's driving us mad and actually making us consider cancelling before our 14 day grace period is up so we don't have to keep putting up with it.

[#2]

All I can really advise is for you to ask the people who are calling you to remove the number from their records as you are not and do not know the person(s) they are calling for. If it continues following polite requests, ask them for details about their company and advise them that you will contact the police if they continue to call you.
Unfortunately there's no real sure fire way for us to stop them calling your number if they believe it is someone else's number. Even if you were to request a renumber of the line, there will always be a high chance of receiving a recycled number.
I hope this helps.