What a surveyor does is to spend between half to one day crawling all over the property, looking for signs that it either wasn't constructed well or that it hasn't been maintained to a reasonable standard. He will look behind things, pull things out, look in lofts, check the services seem to work OK, lift manhole covers, check that construction seems to confirm to building regs in force at the time. He will use a damp meter, look for corrosion or rot. Plus lots more.
If you are a practical person, some of this you can check for yourself, so I wouldn't necessarily agree with the above on a modern house, which this is.
However a surveyor is a second pair of eyes, and I would definitely recommend it on a house older than 50 years.
In terms of costs, phone a couple of RICS people and ask. They work off a scale recommended by their Institute so variations may be minimal. I recently bought a Victorian semi and despite my reasonable all round knowledge of building I did pay for a survey. It cost £700 for a two bed semi.
Pound for pound these people are far more useful than the legal fraternity.