1) You can't transfer your mortgage as such. Once you sell your home, you pay off your mortgage.
2) When you want to buy a home for €295k, it will cost you about €3k in stamp duty and €2k in legal fees, so you need about €300k in total
3) You will have equity of about €200k , so you need a mortgage of €50k
4) If you have a tracker mortgage on your existing property, your lender may give you a new mortgage at the existing margin +1%, but as rates have fallen, this is no longer that valuable.
5) You will not be able to buy the other house without selling your own.
6) If the estate agent has cash buyers for the other house, they are unlikely to entertain offers from you.
7) If they do accept an offer from you, the deposit is usually 10% so €30k. But this is negotiable. But if you don't have €30k, then the auctioneer will probably not proceed.