Sterling mortgage

Just wondering does anybody know if there is an advantage drawing down a mortgage in sterling to purchase a house here in ireland because of the exchange rates at the moment and changing it back to euro in a couple years when sterling goes back to normal levels at hopefully 15-20% gain, if so how would i go about getting it?

Let's see if I have this straight:
You propose to borrow a large lump of sterling and convert it to euros at today's rates, and then pay it back when and if sterling gains value against the euro.

Unless you're talking about a deal in millions, it's unlikely that any bank would be interested in lending in Sterling against a property in the Republic of Ireland.