Land Law: Has Severance occurred?

Hi,

Just needed some help with my assignment as I'm not sure whether severance has occurred. Here's the specific part:

In 2009 Anna announced her intention to leave Buckingham Cottage because she and her son were going to set up home in the flat belonging to her new partner James. Brian (an existing co-owner) therefore agreed to buy Anna's interest in Buckingham Cottage. However, when James changed his mind, Anna and Brian did not proceed with the sale.


Is Anna in declaring her intention to sever sufficient to constitute a severance of the joint tenancy? I am aware that in Burgess v Rawnsley the failed negotiation of pricing was ignored and held that severance did occur. But in the scenario above, does the fact that they both agreed to abandon the sale mean that there is no intention to sever? Also, Anna and Bob are just 2 of 4 joint tenants in the scenario, does this have any impact on the result? (i.e. must they also agree with the other JTs I have not mentioned?)

Any Help would be appreciated. Not asking for any long answer or anything like that.

Thanks