I'm afraid LS drivers are all in the same boat, they are a large car and mine only just fits in the garage which was extended originally to accomodate a Merc S Class and it is still bumper to the end wall and the door just closes.
One thing I have found is most oncoming traffic will tend to get out of your way when they see an LS approaching.
Parking spaces are a joke as others have mentioned,designed for small cars it is difficult to actually fit into them and be able to actually open the doors to get in and out so I find myself parking further away from the supermarket entrance just to gain an isolated spot, having said that there must be an attraction as I often find cars have then parked alongside me.
One good thing is with rear wheel drive the lock on the steering is far better than the front wheel drive smaller cars and it is surprising after a while how easy they are to reverse park into a space, this is also helped by excellent all round vision and nice touches like the door mirrors which dip down when in reverse.
It is really a matter of getting used to UK roads and driving habits at least you are still on the same side of the road here in the UK.
Finally welcome to the LOC and the UK.