Undoing the drain plug on manual gearbox

Hi Folks,
Just working my way through the jobs and gearbox is next. I have bought 3L castrol smx-s gear oil. Got the car in the air removed the cat heat shield (shearing of one of the wing nuts.... Got the drain plug out OK and a small amount of oil dribbled out looking OK, bit dirty but still oily.

However the drain plug would not move at all. Only had a short rachet handle for the very large socket, even under the car with feet on it would not budge. Gave it some gentle taps with the rachet but still no luck. So over the W/E will get alonger torque wrench on to it. How far can I go? I have some short lengths of scaffold tube, about 3 feet long that might slip over the rachet: going to far?
Will also spend 20 minutes or so with a small hammer tapping around and on the plug.

Other ideas welcome.

Then when I put it back:
1)just put it back.
2) Put it back with hylomar universal blue compound
3) Put it back with some loctite?


Suggestions welcome again.

Thanks

The plug will be tight and reasonable force is required to remove it. Do not apply any sealer to the plug when replacing it as it has a tapered

Thanks 47p2, Just in time as will have a go at this tomorrow. I have cut a short steel tube about 18" long to go on the end of the rachet so hopefully that will shift it. Shame there is not a fingers crossed smilie.

Mark