Firstly,Welcome!
With regards to your land and the problem of cutting the grass..... are you planning on expanding seriously into livestock,20 acres is rather a lot of grass to keep mowing! If you're not planning on expanding,how about renting out the fields? Or sell the grass on it for hay? I'm not sure what the law is in the UK with regards to renting out land,but here in France,it's safer to have a contract where one only sells the grass,not rent the land out. Saves a lot of hassle in the courts if you'd like to use the land yourself in the future.
Personally,if I were to be looking at a ride-on mower,and with the amount of land you have,I'd pay a little bit more and opt for a mini-flat-packed tractor.Much more fun to drive and a lot more versatile. Or,trade in your car for a landrover with a pto and decent tow hitch attachment
I don;t envy the decision (or the money you might have to fork out) but I am jealous of the 20 acres and wildflower meadow/woods! Best regards....... Ree