I have noticed my reversing light was not working the other day so put in a new build and still not working.

On further investigation I noticed that the build does not sit tight in the holder bayonet and have discovered this needs to be replaced.

Is this an easy job for a non mechanical person to do

replacing the holder shouldnt be too bad, bit it will require some soldering ability...

It could also be the reverse switch. I had this go on my old 2001 focus. Found the switch easy enough located on the bottom of the gearbox. simply grabbed a spanner and unscrewed it. When i took it out it looked a little like a detonator button (pretty cool I thought!)

Simply went down to my local scrap yard and checked all of the fords there. After about the 10th car I finally found one. I think it was an old Mondeo. I just grabbed the one out of the Mondeo and then took it back cleaned it up a little and fitted it to my focus. The light worked instantly.

Worth a try :)

If you've got a multimeter, put the car in acc without starting it up, knock the lever into reverse, get the bulb holder out and check for a voltage at the terminals. If you don't get a reading, you'll need to change the reverse switch, if you do, then replacing the holder looks like the only option, unless the damage is to the metal bayonet part in which case these sometime can be bent back to hold the bulb properly.