Ok, inspired by a friends FB post, so this is a little rough:
Buying a house is not like anything else - nothing is confirmed until the ink is dry on the contract, and you've actually moved in.
I really recommend getting "The Which? Guide to Doing Your Own Conveyancing" :
You almost certainly DON'T want to do the conveyancing yourself - but you do:
It's up to YOU to make sure THEY don't make mistakes, which are always at YOUR expense (time+money).
This goes for the people you're paying directly (solicitors, bank/lender) and the people paid by the people you're buying/selling from (estate agents, surveyors, their solicitors). I've seen exchange of contracts not happen on a Friday because (it turns out) the sellers solicitor goes golfing at 11am on Friday - but his clerks were still telling estate agents "it may be signed today" at 3pm.
I don't know anyone without a nightmare story, but I know the Which? Guide helped me massively with my last purchase, and every problem I've ever heard of would have been avoided using this book. It does need a (minor, IMO) update to cover 'HIPs' etc.
My "nightmare" was the vendor's friendly estate agent saying "I spoke to the sellers, and sorry, they can't possibly move out early.", so we agreed a date, and my family lived in a holiday home for two weeks (which was ace, but not the point). When we spoke to the sellers face-to-face just before moving in, it turns out the ******* agent never bothered to ask them anything, and moving out early wouldn't have been any problem at all ! We could have even moved in over a few days, saving the cost to us of storage/removers!
So the agent preferring to lie to me, rather than bothering to pick up the phone to ask their own customer a single question - which would have speed up the sale by two weeks and got the agent their commission two weeks earlier as well - this lie cost me around £1,500 !
NEVER TRUST ANYONE INVOLVED IN BUYING A HOUSE!
This includes any banks, solicitors, estate agents, surveyors, drain inspectors, sellers. Basically these professions attract liars. Don't get me wrong, there are some fantastic people out there (Leighton's Solicitors of Bournemouth are great and my sister was a credible 'Sales Negotiator', but error on the side of caution and pessimism.
Talk to the seller (and your buyer) directly and frequently.
An 'update' once a week isn't unreasonable, and more often if you're working through niggly details, like building/drain surveys (I've had a surveyor say "the seller wasn't in", but the seller said the whole family was on the drive loading up a van all morning). Look at it this way, if you were buying anything else for hundreds of thousands of pounds - you'd expect the seller to be very keen, helpful and answer questions willingly. Also it's a two-way street - are they having problems getting a mortgage/removals/whatever? Can you give them any suggestions as someone in the same "boat" ? I've had a solicitor say "the searches are delayed as council has a 3 week backlog", but my buyers got theirs back in 5 days, from the same council. A quick call to the council showed they were turning them around in 3 days, plus posting time, but my solicitor was too busy to submit the form - preferring to lie to me!
Questions like "If the seller's purchase might not happen is this a problem for you? or is that more convenient for you?" are important.
I've been in the position where my buyers would have happily paid £1,000 cash up the chain to the people we were buying from, as long as we could all complete before the end of the month (they were renting and £1,000 was the cost of the rental extension). So often the chain can "work things out" as a group and everyone else is just trying to minimise their 9-5 work.
Before you put in an offer, knock on the neighbours doors.
They are going to be your neighbours soon, so are they friendly, or freaky? (or both!)
Check what the street is like late on a weekday and weekend night, is it all house-parties and kids with hoodies street racing stolen Citron Saxos?
I lived in a street where one person liked to double-park their lorry on the street every night, making it impossible to get larger vehicles past. I'm sure someone affected could have complained, but doubt that would have changed much.