Trouble with my ring

Hi all,
Can anyone relieve my ring frustration
P38 diesel tank pump securing ring will not screw back on without cross threading, no matter how I tackle it.
I have fitted a new tank/pump seal, and pump...does the ring have to be renewed also, or is there a handy tip (abuse expected) to screw the ring back on flat?
On inspection the thread and shape of ring looks good.
BTW, Access is through under seat cut out.
Thanks
Marky.

I haven't even read your post but I'd like to give you a thumbs up on the title...

The only non-technical advice I can offer is......toilet paper must be placed in the fridge for 8 hours.

No knowledge of this specifically but have you tried offering it up square and turning in reverse (undo-direction) till you hear/feel the thread disengage and then slowly and carefully change direction?
I have had success with awkward b4$tard threads with this method in the past.
Good Luck!

Tried it, no joy.
Are you still an Essex boy?
Thanks Dan.

The sender is on a spring ,so you need to push down (and turn the ring the way it came off)it will pop down a little bit thats the start of the threads turn clock wise while still pushing down,it should catch .Tighten ,i,tap it wi a hammer n screw driver gentle taps,job done