Fuel trim diagnostics

Hello, my everyday motor is a 4.6 p38..R reg 170k the usual leaks and runs mostly on LPG....I know but I drive through mud everyday carrying lots of crap and it's such a workhorse..
Attached should be fuelling info from my nanocom, while idling on petrol.
I'm scratching my head a bit...Would I be right in saying bank 1 maybe massively overfueling due to an air leak in the exhaust manifold.
If pre cat stays within 0-5 on both then it's good.
O2 sensor on bank 1 isn't getting all the info it needs or isn't heating.
Am I on the right lines with the following plan,
Swap o2 sensors, check for leaks.
Reset adaptive values, face south, stand on one foot and tap wiring and connections with a mallet while mumbling.
Any help or suggestions would be fantastic as my girlfriend keeps passing out from the smell of petrol in the cab...much to my amusement.

Might be better off shifting this to the RR section as not a lot of people land here.

What's the issue? Long term trim is 0, which is ideal

A short term fuel trim that high, I would be looking for a vacuum leak on bank 1, as the ECU is seeing a lean condition, It could be as simple as a faulty lambda sensor, maybe a cracked or blowing exhaust manifold.

Too much oxygen is being read by the lambda sensor, I'd start by looking for a vac leak, or exhaust leak before the first lambda sensor.