Aston DB7 Vantage differential oil change questions

[LuFuS]

Hi guys
I have recently bought an Aston db7 vantage.
Have had some service done, engine oil, oil filter, air filter, brake fluid and so on.
But would like to do an oil change on the diff and the transmission.
The T56 transmission I find plenty of information on, since it is used in many cars, but the diff appears to be a black hole.

Seems like it was not intended to be replaced as part of service, but it is 20 years old, and i dont believe in this oil that lasts a lifetime.......

Looks like the rear x-brace will have to be removed, and then access should be ok for drain plug.
Fill port appears to be on the rear of the diff, just below the speed sensor.
But not sure about access, and dont want to start this and end up with total failure, so appreciate someone who has one this can enlighten me and others.

So would very much appreciate input from someone who has performed an oil change on the DB7 Vantage diff.

Picture DB7 from below
http://www.astonsaleskensington.com/Upload/minigal...

Diff - showing fill plug
https://i.ebayimg.com/images/g/dXUAAOSwj99aBGi2/s-...

Diff - below - showing drain plug
https://i.ebayimg.com/thumbs/images/g/VAkAAOSw4z5f...

Thanks alot for any support!

[Prattking]

Although I've never attempted changing the diff. oil I've read that you must make sure you can undo the fill plug first. It can be difficult to get out so if you drain the oil first and then can't fill it you have a problem.