[DaveNP]

I sit on both sides of this dilemma, whilst I've just spent over £200 on parts (that I'll fit myself) to keep the V70 going my wife's car is a 2 year old Kia Stonic. The old car, even with the repair bills, is overall much cheaper than the new one with its depreciation but she wants the peace of mind and that's what we are paying for, whilst you mention the £500 bill for your mum's car I sense that the more important factor is that peace of mind for her and thereby for you.

In terms of what vehicle to go for in the newer category it seems most cars are pretty good these days with the Far East manufacturers having come up to match the traditional European marques and most have some sort of extended warranty (Kia automatically carried the warranty and service plan over to us, other manufacturers may charge or have hoops to jump through).
We managed to find the wife's car at a main dealers just under a year old, apparently the guy who bought it changed job so traded it in for an all electric car to use in London, he must have taken a massive hit for the depreciation as we bought it for about £16k compared to £21k for new.

In terms of what to buy/ how to 'buy', I basically took my wife around all of the local dealerships to find the model of car she/we wanted based on its shape and look, and then researched the best options in terms of engine,transmission and trim specs, having got that sorted it was then a search for a nearly new one to buy outright to make the most of our money. If the Note is running well enough for the moment you do have the advantage of being able to wait for a good deal to come along.
Colleagues at work have recently bought cars from Cinch and Cazoo online and been pleased with their cars and the service they received but while they seem to have fair/competitive prices they may not have the cheapest deals.