If you have an R380 box as my 1999 +8 does, Torx T55 required for filler key and I use an oil syringe to fill up, Draper do them...

[video:youtube]
[/video]

Yours could well be an LT77 being a 1993, though same procedure.

[video:youtube]
[/video]

2009 4/4 Henrietta
1999 Indigo Blue +8
2009 4/4 Sport Green prev
1993 Connaught Green +8 prev