I agree with architectming ( great name!). We actually extended our property but the final price was something closer to £180k. Even without the extension, I can tell you that other issues we had to rectify included:
Below-par water supply (supply pipe old and too narrow to support today's water demands) - £850 to replace
New gas supply pipe (gas board insisted on it) £600
Replace internal glass to standard safety glass £500
Re-roof (tiles only) £3.5k
New garage door £2.7k
New front door £500
New driveways and patio (existing were crumbling) £7.7k
Replastering £3k
New burglar alarm £800
Rewire with new consumer unit and chrome fittings £5k
New internal doors and handles £1700 plus fitting.
Cost of renting another property for four months £4k
Also, the big things led to lots of little things. For example, the rewire led us to need new TV aerials all through the house. The replastering led to new curtain rails. All of these little things add up. Or house was literally stripped out, there was no doorbell, no coat hooks, no toilet seats.
We've been in for about 15 months now and we still have a long list of jobs to be completed. We have one window left to replace; 3 rooms with No curtains, 4 rooms without light fittings. We need to returf the lawns (quote £2000), we have no wardrobes in our bedroom. And this is before you even start on the fact thator 'old' furniture doesnt quite fit into the new house ( we have extra bedrooms that need filling!).
It's been a long hard slog and its knackered us financially in the short term (just getting better now). For the money you describe, I think you will get the basics done, and if you are happy to save up for the rest of it, yes it looks as though this house is a great opportunity. You just need it be sure that (if you are increasing your mortgage) you can afford the other things on top of the new mortgage.