Advice - the the math - at a crossroad

Hi all,

I have a dilema similar to Carter88. The scenario is that my wife and I have been renting out our property whilst the kids were young and the property is now empty so we planned to sell in order to buy a new property to live in (we've been renting for a few years from family).

However, I'm very tempted to keep it and buy another to live in. The current property has had an offer of 250k which we know it is worth (coud get a bit more if not for that pesky tax).

Current property value 250k
mortgage remaining 47k
new house value c280 (incl pesky tax)
rental income - was 1100pcm (agents/market says we could get 1200 at least)
joint income (work) c3kpcm

So is there a formula that I should use? Do these figures loog good for the keeping of the old house?

BIG QUESTION (could also be stupid) - if we went ahead, I see it as a little bit of extra each month with the benefit of a nice cash lump at the end (of around 100k net after selling property and repaying the lender around 150k if house prices do not change at all...). Is this the right way to look at at it?

Or do we take the straight-forward route of selling and buying our home without the fuss?

Thanks all.
H