taking partner of joint mortgage

Lisa1919

Hi , currently going through a separation and looking at the best way to take over the mortgage. I had a house previous so the money in the house is mine but it is in a joint mortgage. I rang my mortgage provider and to take my ex partner off I would have to reapply and meet the eligibility. They could only lend me £150k and my mortgage is £201k , I earn 34k a year. 

My dad was happy to be a guarantor but Barclays say they no longer offer these mortgages. 

Just wondering what options I might have and whether it is possible to try and get a guarantor mortgage  and pay the fees to come out of this one.
also someone mentioned severe the tenancy agreement as I am in a three year fixed term but would my ex partner be able to get proceeds from the house when I sell?
many thanks