I am hoping Xena is now fixed, the new part arrived this morning.
I cut part of the housing off with a dremel to get better access to the seal, separated the bellows from the rest of the housing without any damage, cleaned everything up and applied some silicone gasket maker and put it all back together, left it to cure for about an hour while I had some dinner.
Refitted the cover and filled with coolant and went for a ride, there seemed to be some fluid coming out but it was not running out like it did, I think it could be some residual coolant from before as it just seemed to bubble as if it was purging itself, will see how it is in a while and will take her out again later and see if all is well