I would be worried that as well as the cosmetic and very obvious stuff (eg bathroom, kitchen, walls, flooring, clear garden) there would be a bunch of (probably expensive) stuff to do which wouldn't be obvious until you'd had the survey done. Such as damp work, repairs to the roof, re-wiring, replacing soffits and fascias, drainpipes, re-pointing brickwork, replacing or removing chimney stacks, woodworm etc etc etc. Has it got double glazing? Cavity wall insulation or loft insulation? All this stuff can really add up.
So you might estimate the cost of all the obvious work, buy the house, only to find that the owners have basically done no maintenance since the 1920s and you have a whole load of unglamorous but expensive maintenance work on the house before it's habitable /safe. Can you go round it with a builder who could try to spot those things too, to add to the things you can see?
We bought a house a couple of years ago which had been the family home of a couple for about the last 30 years and they'd done very little maintenance. The house isn't falling down, but I have a big list of these kind of unglamorous mini projects when I'd really rather be spending our surplus money on holidays, nice food etc etc!
And having done our kitchen and bathroom since we moved here, thinking "we'll go for something basic" I am still amazed about how much "basic" costs. And then you think "might as well do it nicely since we're staying here" and it costs even more.
Sorry to sound doom-and-gloom but of course you want to go into something like this with your eyes open!