I think i may have found a solution that means i dont have to remove the fuel tank
I found a 1/4 BSP thread (with some ptfe tape) will fit into the fuel union and has an 8mm barb connector that will take the short section of fuel hose allowing me to do the fix in situ
the first pic shows the top half of the fuel union and pipe that connects to the fuel pump - the pic shows the spare line that i have so will replace the whole pipe (accesing via the inspection hatch under the rear seats).
I can then cut out the small section of hard line that has the hole in it and connect it up with the fuel hose.
The 1/4 BSP fitting was closest that i could find but it is a little bit loose so will need a bit of ptfe tape and fingers crossed for no leaks.Thats the plan - will have to wait and see if it actually works.