Bumper off is an easy task, if not a little fiddly!
There are 4 or 5 under-tray bolts / screws (essentially all of the ones on the front edge that look like they bolt into the bumper). Then there are 2 more bolts underneath the wings just in front of the arches. (these will be a combination of star drives and phillips or bolts depending on how much of a pig your under tray has been in the past to come off!)
Once that lot is done you can move onto the wings. Start the engine and give the steering full left lock so you can easily access the right inner wheel arch. You will see 2 screws, typically Phillips, but they could have been changed during the life of the car. Remove these 2 screws. Where the bumper meets the wing on the inner arch there is an 8mm bolt facing directly upwards so crouch down to see it. Remove this as well.
Now move the steering to full right lock and repeat the process for the 2 screws and 1 nut on the left wing.
Once that is done all that is left are the 4 star drive bolts on the top of the bumper, visible when the bonnet is open. Remove these and you are ready to release the bumper.
To release the bumper, from the inner arch, tap (hard) the edge of the bumper towards the front of the car as if you are trying to push it off. It will move a few mm and loosen slightly then you can pull it out towards you and it will come away several inches. Do this on both sides.
Once the sides are free you can lift the bumper over the bonnet release catch and it will all come forward and off the car easily.
Trust me, it sounds harder than it is! Coxy showed me how to do this while his car was in bits and it really is very easy. It was even easier than taking the under tray off to clean the air filter as I could remove the whole air box with just one bolt and a pipe clip. This turned out to be useful as some of the bolts in the box were turning freely and needed a lot of effort to get out so it was much easier to do with the box on a bench rather than on the car from underneath!