Receive the call while I am aborad

[avocadot]

Hi,

My phone number is linked to the door bell, and I am going to travel for 2months and want to only receive the phone call from UK to UK number while I am abroad(not in EU/UK, international country). 

I found the £5 monthly add on service, I just want to make sure what is the best option in this case?

[avocadot]

*Note : And I want to not spend any data to avoid extra charge, only need to receive the call. thx