Hi - when I open the boot lid after rain there is water swishing about inside the lid itself. Do not know where entering?????

first of all.. the boot should have some drains, check to see if they are clogged.

the water can come in in numerous places... like the boot handle.. the glass, the spoiler, next to the spray nozzle..etc.. you just have to check.

Take the interior plastic off the lid.
Get rid off all the water, then dry with paper towels.
Take the car to a pressure washing place explain what you want to do... and while you are in the car the guy moves the pressure washer lance through different places... you watch for drips.. and feel with your hands.... (that's why you need to dry the lid first).

First suspect the rubber seal between the wiper arm and the glass. If in doubt seal it to the glass with silicone sealant. Then check the light units in case they are leaking. If your car has lights either side of the number plate (earlier 5 doors did, not sure about 3 doors) these would need to be checked.

most common is the back of the tail lights - the rubber seal on the back does not cover the hole for the wiring properly.

Thanks for replies - tail lights on a 3 door do not go onto boot lid - only estate I think