I took a risk and proceeded with my upgrade and all seems to've gone
well except my main page told me,
If you have just upgraded MediaWiki
MediaWiki 1.24 and newer no longer automatically enables installed skins
(see Manual: Skin autodiscovery). You can paste the following lines into
LocalSettings.php to enable all currently installed skins:
If you have just modified LocalSettings.php
Double-check the skin names for typos.
I did all of the above, and cleared my cache, but the error still appears.
Anyone know what obvious thing I am ignoring?