Cash only house sales

Look up Mundic Block and decide if you want to take the (usually minimal) risks involved.

There could be a load of other reasons but the possibility of degraded concrete is a regular one.

or the house could be built on top of old mine workings!

Look up Mundic Block

An issue with concrete in Cornish homes generally built before the 1950's

Not really something you'd need to worry about up here.

True; but also look-up "Black Ash Mortar" and "Wall Tie Failure"! https://www.bing.com/search?q=Black%20Ash%20Mortar&pc=cosp&ptag=C1A005A2B4283&form=CONBDF&conlogo=CT3210127

Listed buildings can be tricky too, especially if it's a non-standard conversion of something.

Daughter and boyfriend are currently looking to buy their first home . Yesterday they saw a couple of houses in their price range but they were cash only sales . Can anyone explain whats in it for the seller or the buyer in a cash sale ?

Buyer can move faster with cash - no need to mess about getting a mortgage (and potentially being turned down causing the sale to fall through).

In areas of high demand I have heard of no chain requirements if you want to buy. Just look at Bristol. Specifying it further to cash only makes no sense. In fact I would stress on getting a mortgage as it will go through all the checks by the bank to ensure that the property is mortgageable and hence will have decent resale potential later as an option.