fuel sender unit

Hi I'm about to drop my diesel tank on 300tdi disco 1997.
Typical hoses have corroded . I was wanting to know what size of coupling is the one with the olives . where the plastic joins the steel pipe at the sender unit. I know the pipe is 8mm od . can any one help ?

why drop the tank when you can get to sender through the hole in rear floor
try googling nrc9771 and nrc9770

Sorry maybe I wasn't clear dropping tank to do some welding . When I noticed the pipes to the sender were corroded so from 30 years repairing them I new they were gonna be knackered. See normally for a customer at work you just throw a new sender unit in. but my rebuild is on a tight budget. so I'm going to repair my sender unit . So I was going to fit a female hose tail to the union on the plastic fuel pipes . I have cut the corroded hose of the sender cut away the plastic elbow around the steel hose in the sender to exspose
1 1/2" of solid fuel pipe to connect to.

all sorted the thread is 12mm x 1mm pitch sender unit good to go