We are a group of Shias in the UK, called Edinburgh Ahlul-Bayt Society. Since traditional places in our city do not have minimum safety standards required for having formal courses particularly for children, we are holding our events and Shia courses for children in common places including old churches.
The reason we are using churches is that they are no longer an inclusively christian places, but they are used mainly as social and common places for community events.
Obviously, we are more than happy to use Hosseinies, once they have required legal features.
Regarding the opposition of conventional communities to this plan, we would be very grateful if you let us know whether or not it is permissible for us to continue using such places for our Shia events.
May Allah guide us for the sake of Ahlul-Bayt.
The Edinburgh Ahlul-Bayt Society”
Eminent religious scholar’ name:
The supreme leader,Grand Ayatollah Khamenei
It is not permitted if it makes mischief or if it propagates and confirms null and void. 
 Provinces sites, exclusive to the supreme leader’s represantatives, question section,Istifta NO : ۴۱۲۷۳۱