no bother,
this is your own choice obviously but if it was up to me I'd sell the current house for 275K, bag the 183K and enjoy life having a much lower mortgage in your next house - go for 2 or 3 holidays a year and live for the now!
remember when you eventually sell what would become the investment property you'll have to pay capital gains at 25%. Unless your current property is in the centre of a major urban area I'd get rid of it (and by that I mean only Dublin and Cork).