Unfortunately it's an illusion that debt can be compartmentalised, with an unsecured debt having no impact on property.
£25K of debt, if defaulted, could start bankruptcy proceedings, which would involve the equity available in the house, and property sale.
A more likely route would be that if the 'unsecured' debt defaulted it would end up in county court, with a CCJ issued. The CCJ would then have an agreed repayment schedule. If that was defaulted then it would return to county court, a 14 day repayment in full order issued, & if that was not met a charging order would be issued against the property, and sale would be enforced.
Speak to a debt adviser at your local CAB or Advice Centre if you need to confirm this advice, but I'm afraid that 'unsecured' is a misnomer if you own property, it just means that the value of equity was not explicitly considered when the loan was granted. Why do you think so many companies that offer 'unsecured' loans will only do so to home-owners...