How hard is it to change the rear discs ? I’m thinking of doing it myself , looks easy enough .
It is!!
my mum could do it with 5 mins tuition!
What does your mum do for a living though ?
she owns a cleaning company. (but did a bit of rally co-driving in her youth) 
Cool , I will give it a go then .
Drift out the caliper retaining pin
Remove the pads
Undo the disc retaining screw (some are difficult to get out)
Then remove the disc (no need to take the caliper off even)
Assume you are replacing pads in which case recommend taht you will need the caliper piston adjusting tool.
A good option is to use a pair of needle nose pliers to wind the piston back in if you don’t have a special tool.
Also the small disc retaining screw can be a pig to remove. I would get 2 new screws from Dave at Seriously Lotus as you are sure to damage them when removing. I needed an impact driver last time!
Thanks , will order some screws , do I need to remove the pads if I’m not changing them ?
Take the pads out to get enough room to get the discs off the hubs
Yes you need to remove the pads to free up the disc.
If your discs are at all uneven you may want to replace the pads otherwise they will try to grind similar patterns on you nice shiny new discs. I guess this is generally less of an issue with rears than with fronts but if the discs are scored I would suggest new pads.
Yup
Ok ok new pads as well then ! Lol 