DO NOT buy a "Spare wheel holder" ...go to the local Builders merchant & buy a length of 6mm threaded bar (Comes in 1 metre lengths) 2 Nuts & a hand ful of washers ..+ bout 1 metre of 4mm ply board
Thread the bar up thru the hole, measure & cut...... nut & washers on the end (Under the car) nut & washers inside car (at bottom of Wheel well) place wheel over bar sticking up, cut ply to same width as wheel & drill a hole in it at the centre place ply on threaded bar down to top of spare wheel washers & nut to tighten.....
SORTED!!!!!!!!!!!!!
Totalr cost ..Bout 6 quid