Over the last few days I have a constant whining noise which gets louder and faster when the accelerator is pressed. It's there whether in park or neutral. Could it be alternator, idle pulleys or tensioners? If so, are these jobs easy enough to do? Changed my coils and plugs already, what an improvement there. Also can't open front passenger door from inside or out, or using remote.

Cheers, J

If you trickle water over the auxiliary drivebelts and see if the noise goes then its just dry belts causing the noise.

If it doesn't go, then possible tensioner bearings, etc

You have an alternator, AC pump, Power Steering and Water pumps plus the tensioner. I would first check the belt condition as a frayed belt will make strange noises. I would also check that the cooling fans are operating as they should AFAIK the 4.8 has electric engine fans. Replacing the tensioner and belt is good practice and while the belt is off you can check all the other pulleys for any side movement and free running.

To fix your door lock you will need to remove the door card and peel back the vapour barrier to get access to the lock the issue will be corrosion on the lock mechanism if you use the search function we covered this recently in the X5 section

Hope it's all simple fixes Good luck

Very common for these belts to whine over time.