If you are looking at a £250k house then do the simple sums. I'm convinced that if the mortgage payments (plus maintenance costs) are more than current rental costs then it's just not worth buying. We were lucky to buy some time ago but if I was in the market now I wouldn't be trying to buy. I am currently trying to explain to DB that he really shouldn't be worried owning a house.
Our house was valued 2 years ago at £265k or rental income of £850 a month. If I could buy it on a 75% mortgage for @£1150 a month or rent for £850 a month then it seems I would be paying £300 a month plus maintenance costs more than I needed to.
Explain those sums to your mother, ask her if she wants to chip in the £300 a month!