I'm going to take issue with Dan North's accepted answer, not that it is bad, but let me put my own perspective on it. I am a Canadian, but spent most of my life in Scotland, learned to drive there and did for nearly 30 years before returning to Canada a few months ago. During this time I also did regular (2-3 times a year) multi-week driving stints on holidays in Europe (France, Spain, Greece), so hope to have some insight.
Driving on the opposite side ISN'T THAT HARD (takes me about 30 secs to re-orientate after doing it for years). Yes the first hour or so on your first ever drive on the other side is pretty scary (ironically I found it best to start on a big motorway where you could cruise and get your bearings, small roads in town are much harder).
The thing for you coming from Europe is that the roads behave in a similar way - signs are similar if not identical, motorway lanes are more familiar, you'll be used to how roundabouts work etc. I found driving in Canada much more of a shift - right turns on red, left filter signals, 4 ways stops rather than roundabouts, motorway free-for-alls with people just ignoring speed limits (fun to be doing 15 over the speed limit in the middle lane on a big highway and have 10 cars undertake you at a much higher speed), different words on some signs.
This brings me to my issue on using a P plate. Drivers in Scotland are not forgiving, you can see them venting frustrations as they have to overtake learners in branded driving school cars (that can be recognised half a mile away), and the feeling I suggest would be as a P plate (even a pretend one), you are supposed to know how it all works and get on with it. New drivers I've known have discarded P plates in a few days as they felt less pressure without one.
To me the biggest hurdle will actually be your LHD car. One of the cues for my brain (at least in Europe) is changing gear with the opposite hand (so not done by muscle memory). I would find driving on the "wrong" side of the road in my normal car very disorientating, especially at roundabouts, and I would hazard getting a right hand drive car would make things much easier to acclimatise.
I would additionally suggest getting the LHD car registered in the UK will be difficult. You'll need very good evidence of the age of the car to avoid getting a Q plate which will make the car much more expensive to insure and harder to sell (cars in the UK are more identified by number-plate rather than VIN, and have digits showing the age, cars of unknown or questionable age get a Q reg). You'll need to get the UK reg to get insurance for the car in the UK, and you'll find at sale time most dealers won't touch a LHD with a 10 foot pole.
So I would just ditch the LHD car, buy a UK one (yes it will likely be older as I'm assuming you are bringing it to offset the high price of vehicles in the UK, it isn't some classic Bugatti), and a couple of good runs will bring you the confidence you need, the more you make issue of it being different (by sticking in the LHD), the longer it'll take to acclimatise.
So in summary, my answer is Don't make yourself more visible, you'll be better treated, and get used to driving in Scotland much better by getting a UK car and blending in.