Having just carried out an oil change on my IRD box, which was a bit messy using a 60ml syringe, I then turned my attention to the Manual Gearbox. The filler plug had a Torx fitting head and was so tight it rounded off as I attempted to remove it with the appropriate Torx tool. And that leaves me in a quandry. I'm going to have to use a chisel to drive it round and hopefully off, but refitting it will not work. I need to replace it, with hopefully a hexagonal or Allen screw head. Never a Torx.
Can anyone advise on an appropriately sized plug that would fit so I can have one before I attempt to remove the original plug by force?

There are a couple you can chose from, the one on your car should have been Allen key, but as always double check the part for fitting before purchase.
https://www.brit-car.co.uk/product.php/133329/3008/drain_filler_and_level_plug_freelander_1
https://www.brit-car.co.uk/product.php/94342/0/plug_drain_filler_level_transfer_box___freelander_1

good tool to remove the filler plugs on the TD4 M47 engine
https://www.ebay.co.uk/itm/Drain-Su...h=item5d749e77b5:g:mD0AAOSwxzBZmvyc:rk:4:pf:0