Are you saying that if you can see another car on the inside lane regardless of how far ahead that may be then you will stay on the middle lane?
Possibly. Entirely depends on the context.
If I was obviously gaining on that car and the road behind me was clear then yeah, I would probably just stay out.
If there were cars behind me then I'd pull in if I thought I'd be in the inside lane for more than say roughly 20 seconds.
I definitely wouldn't pull in if I'd only be in the left hand lane for a "couple of seconds".
The Highway Code clearly states that in a car travelling at 70mph you should keep a distance of at least 75mtrs between your self and the vehicle in front.
Does it? That seems a little odd since the official stopping distance at 70mph is 96 metres.
Sure you don't want to go for those lessons? 😉