The last couple of times I have come back to the car after putting it in access mode, it looks to my eyes anyway, that it is sitting very low on the driver's rear wheel.

The warranty expires this week, so I have booked it in with the dealer to be sure but is this a concern? I have to do a few hundred miles in it over the next few days.

You need one of these to check it with and go from there.

Have you measured yourself, just a simple tape measure would do. I did recently as I thought it sat too low at the back (turns out the back is supposed to sit a bit lower) and found a few mm difference (not bad I'd say).

In Dutch we say "meten is weten" (although strictly speaking the term should be "meten is vergelijken" but that doesn't rhyme

Once you have the numbers, you know for sure and how much. It may be just a simple calibration of the EAS to get it sitting perfectly  MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!