Re: P11 steering alignment
If you're saying the bar does not look right in the clamp (one side farther back than the other), I would guess the bar is crooked, probably from a minor mishap. If it's not centered in the clamp, then loosen the allens and center it. I doubt the top triple clamp is tweaked - it's pretty tough. Fork tubes, on the other hand, can get tweaked easily, but are available from several suppliers (at about double the cost of Norton tubes)
My Ranger came with front end damage and a non-original handle bar. New spindle, fork tubes, left slider and correct bar fixed all that. That minor crash back in the '70s probably saved the bike. It couldn't be fixed 40 years ago due to unavailable parts, so sat until I found it.
40 years ago the only way to find parts for these things was to go to swap meets. An 8-10 year old bike was not worth restoring for many folks.
Now the English bikes people remember are all 40-60 years old, and forums such as this mean one can resurrect one in as little as six months, given enough money and determination.