First up was the boot struts which need replacing. They had been weak for a while, but had recently completely failed meaning I had to hold the boot up myself (which is surprisingly heavy!). You have to be careful when buying boot struts as quite often, aftermarket ones (even from good manufacturers) can be way too powerful and launch the boot open. This could obviously cause damage to the body where they attach. The important thing to do is to make sure they are the same force as the factory ones, which is measured in Newtons, and usually stamped on the strut.
The Genuine Mini (made by Stabilus) are £90 for a pair from the dealer, but I managed to get the OEM Stabilus ones for £26 delivered - so a great saving. The Genuine ones even say "Stabilus Lift-o-Mat" on them so it just demonstrates again how much manufacturers make in part sales. The struts are 330N (not 310N as listed on RealOEM) and the Stabilus part number is 0746VC.
(Old Genuine ones at the bottom, new OEM ones at the top)
To remove the old ones get a small screw driver and prise off the thin metal retaining clips at each end (watch out, they do ping off and go a long way!). There is no need to remove them. The old ones come with new retaining clips, but leave these alone as the arm just clicks onto the ball joint. If you get rubbish struts you might need to stick some grease in the hole where the ball will sit, but the ones from Stabilus came with a blob of grease already in there.