loss of cold water only to one room

[Hunni]

I have a very temperamental ensuite that lives at the front of the house but on the attached house wall with next door. Last year it lost all water which turned out to be a freeze related issue. This year its just lost the cold water. opened the tap and got some water and then nothing heating is on full but how long does it take if there is an ice block somewhere under floor? Is there anything else I should be looking at other than a potential freeze issue?

Thanks