As always when working underneath a Car make sure that it is well supported.
A Scimitar landing on you will give you a sense of humour failure.
Unfortunately when I completed all the work on the Engine and Gearbox I did not replace the Gearbox Selector Oil Seals. I had read that they can be replaced without the need to remove the Gearbox or to remove the Gearbox side cover. I thought that this seemed a bit fiddley so I replaced the Seals by removing the Cover. The job was very easy and showed me that trying to replace the Seals without removing the cover was a bit risky as there is a real possibility of the selector shafts being pushed in. If the first/second or third/fourth shafts are allowed to move in more than about 3/4 inch there is a real possibility that the internal locator balls will fall out. Not to much to worry about as long as you can find them and that will require the removal of the side cover. I thought it would be better if I removed the side cover, the whole job took just over an hour which I would think is a lot quicker than trying to lever out the old seals and trying to fit the new ones over the shafts. Before starting make sure that the gears are in neutral. The following pictures should be self explanatory ?. All pictures are expandable by clicking on the required image. There are exploded views of the Side Plate at the end.
Drain Oil from Gearbox.
Remove Selector rods.
Remove Bolts that hold Cover. The Cover may be reluctant to come off but gentle levering at the edge will remove it.
You will now have this on the Workbench.
Note that the 1st/2nd and 3rd/4th levers removed.
The other side of this plate looks like this.
If the Selector Shafts are pushed through these are the balls that will fall out.
The Seals look like this.
Note Seal removed ( Reverse ).
As all the good books say assembly is the reverse of the above. Gently push the new seals in place then use a piece of wood and gently hit flush, there may be the need to put a "Socket" of the same size over the seals and give a last thump. Before refitting the Cover make sure that the 1st/2nd and 3rd/4th selectors are in the center position, that is the balls are in the middle groove. When refitting the selector shafts through the new seals check the shafts to ensure that there are no rough edges that could damage the seals as the shafts slide through. One slight problem is compressing the spring that pushes on the balls. The first ball is easy to fit but the second one can be a bit of a sod to hold in place while you push through the shaft. I found if you use a small screwdriver and push down and toward the shaft it will locate. When you try this the ball will try to make a bid for freedom so do it in an area that will allow you to find the ball if it should escape. Good luck although you should not need it as this will be one of the easier jobs you will have done on your Scimitar ( Assuming you can crawl around under a Car without the need for assistance to get up. I have found the older I get the further away the ground seems to get ).
Below is an exploded view of the side Cover.