Laurie,
You say you have oil leaking from the front of the gearbox. Is that with the gearbox in it's normal position? If it is with the gearbox stood on it's bellhousing - it's OK - it is designed to do that! There is a drain from the main shaft, through the figure '8' plate to the layshaft, that feeds some oil to the front layshaft bearing. This drain also acts as a breather for the gearbox. Some owners have in the past replaced the front layshaft bearing with a sealed bearing - this then blocks the escape route for any oil that gets past the mainshaft seal (as well as blocking the breather!).
If you haven't yet managed to shift the drive coupling, undo the 6 nuts and remove the figure '8' plate - it should come away complete with the input shaft, but leaving the layshaft and mainshaft behind. You will then be able to check that you have the correct front lay shaft bearing (if it has been replaced with a sealed bearing, just knock the seals out). With the front plate off the 'box, leave the securing nut about 1 turn undone, and keep squeezing the coupling in the vice, moving round 1 spline at a time until the coupling works loose on the taper (it may be stubborn, but it will eventually give up).
Hope this helps,
Regards,
Eddie.
