I'm an EV lover.
Do not buy a diesel - with issues over diesel cars, fuel prices and cities looking at banning diesels in the future, it is all going to affect re-sale values.
If you want to go with a fossil car then pick petrol.
I'm not a massive fan of hybrids. If you want one, you want a plug in hybrid - the others have such small batteries that they may as well not have them.
For the plug ins, the Mitsubishi PHEV is popular and you can pick a second hand one up for a decent price. The issue is you do have to make sure you charge it and use electric when you can. It was popular as a company car as it is low tax, but people were then not charging them and they were actually less economical to just use petrol than a regular ICE car. Charge it up and you will cut your costs.
I am a pure EV, but they do have their drawbacks. They are not there in the second hand market yet, so to get one with a good range you are looking at at least £15-£20k upwards. The cheaper ones have a smaller battery. If you live somewhere flat, that is fine. Mine has a 24kwh battery and can realistically do 70 miles on a charge (although in the cold we are only getting around 45 miles on the last charge!). Take it on the motorway and it is a lot less so you have to factor in stopping and charging.
If you went for one, you would ideally want to go for at least a Nissan Leaf 40kwh, the newer model Zoe or one of the newer ones, but the price is still high.
The Leaf and Zoe have small boots, so for what you want you would really want either the Hyundai Kona which is an SUV type electric car (they do a hybrid) or the Kia Nero which is SUV type EV that is bigger than the Kona and due out in the next few months. The problem is the cost - the Nero is going to be about £32k when it comes out and it will be a few years before the second hand ones come through at an affordable price.
Volvo are due to bring out a V40 electric soon, but for the type you want the car and price may not be there for a few years.
Sorry this is so long!!