Hello, welcome to the forum.
£750.00 is $1,377.60 USD and for that money, you could easily afford an M3 Coupe, which is what I would go with. I would go with that car because it is arguably the greatest sports car on the road (particularly for the price).
I would also probably buy the car because the BMW M cars have very high resale value, I could keep it for as long as I like, and I can feel free to mod it.
Leasing the car is a good idea if you use it as your daily driver, you know how much mileage you put on the car (yearly), and you just pay the easier monthly payment and you get a brand-new car in 3 years.
But correct me if I'm wrong, don't you have to pay a lot more money for your cars? I mean, even including the exchange rate, a Range Rover here costs about $75,000 USD. But doesn't a Range Rover over in England cost around $130,000 USD?