Mixed tyres on Freelander 2

Just bought a 2012 Freelander, checked the tyres were ok, but now I have it i notice that on the front are two new looking budget tyres and on the back a newish tyre, with plenty of tread, and an older one with noticeably less tread, which was over inflated. New to Freelanders, what should I do? It doesn't have a spare, maybe but a rim and use the good rear tyre as a sparespare?

To avoid diff damage on a Freelander 2, make sure that tyres are of equal tread depth on the same “axle”. So, like you say, fit a new pair to the rear and keep the one decent one as a spare.
There are plenty of single rims that you can put it for sale on eBay.

Thanks will do. Have bought a rim a complete with tyre! Tyre isn't bad so will have two good spare tyres. Plant holders?