How many miles do you do a year?
It seems like you are about to spend a seemingly mindbogglingly large amount of money on a completely ordinary car for no rational reason at all. You've got £20k in cash kicking around yet are finding 45mpg heavy going and free road tax rather than £120 a year appealing?
As with every thread you have ever posted on this forum it yet again makes no sense.
Buy a used Golf or something for £9995. Don't let trivial costs like insurance differential and road tax influence such a huge purchase. It's just nonsensical.
If you really want to buy a brand new ecohatchback then test drive them all and buy the one you like best, you'll have a warranty so reliability doesnt matter and frankly most of them are all much of a muchness. I'd probably have the new Focus though, the Leon is absolutely ancient and well past its sellby date.