I have recently seen several post face-lift S-Types where the owners had no idea that they had power folding door mirrors.
It seems that such conveniences are soon forgotten and as a result, dis-similar metal corrosion takes hold and seizes the bearings.
So - do you have power folding mirrors?
Unlike the post face-lift cars which had an additional switch in the driver's door pocket, the later cars have no visible indication.
To operate the power folding mirrors post face-lift, ensure that the mirror selection switch in the driver's switchpack is set to the central position. Then press the circular positioning switch momentarily down at the rear most edge of the switch whilst watching your mirrors and listening.
If your mirrors move smoothly in and out with alternate presses of the switch then all well and good
If there is absolutely no discernible movement or the slightest creaking or clicking sound then you probably don't have power folding mirrors (simple enough to retro-fit though).
However, when pressing the switch you might see the slightest twitch from one or both of the mirrors and / or hear a slight sound contemporaneously with the operation of the switch. This means that you have seized or partially seized power folding mirrors.
My suggestion to free them off is as follows and has been tested on several S-Types with success:-
Pop the mirror cover off if you can. Usually this can be achieved with a little judicious probing with a fine edged trim tool or CAREFUL probing with a small screwdriver. PLEASE be careful though as the clips are prone to break, especially in cold weather.
In addition, if possible, remove the small lower pivot cover to give even more access.
With the cover(s) off you will almost certainly see a load of white powdery corrosion. Brush this off as much as you can. Now, the ideal solution would be to dis-assemble the mirror and give it a darned good clean up but this option appears to be next to impossible, but I'll be grateful if somebody can gainsay me on that .
Instead, use a can of spray lithium grease and spray the area of the pivot bearing copiously including externally straight into the joint between the fixed stanchion and the mirror body. Allow a few minutes for it to penetrate (the pressure of the aerosol assists in forcing the lubricant to where it is needed), then, with the engine running, to keep the battery charged, operate the switch and at the same time physically move the mirror on one side of the car. This is best done with two people for the driver's side and impossible to do without two people on the passenger side.
You may need to be a little robust initially but feel for the mirror trying to move and then assist it to either fully retract or fully extend. Once the mirror moves full range with assistance you can then gradually reduce and then stop the assistance to gauge the efficacy of the lithium grease.
Be prepared to take some considerable time doing this. The longest I've needed was 40 minutes. However the combination of the forced injection of lithium grease aided by the physical assistance will eventually free the mirror pivot up to the extent where it has free unassisted range of movement on both directions for most of the time. Further applications of lithium grease will assist as you progress.
Once the mirrors are moving reasonably well, you can replace the covers and clean off the excess grease from the bodywork. Lithium grease is unlike normal grease in that it will quickly disappear when polished off with a rag.
SOMETIMES, you can achieve the same result without removing the cover, just by spraying the grease into the joint. However, I would still advocate removing the covers to get a more comprehensive job done.
Regular operation of the mirrors will keep them moving freely although you might like to add the lithium grease procedure to your normal maintenance, perhaps on a bi-monthly basis?
The following Youtube video, which is not mine and which I hereby acknowledge the originator, may be of assistance but you really do not need to go to the trouble of removing the complete mirror assembly from the door, or removing the mirror glass, in my judgement.
S-Type door mirror maintenance
I hope this is of help