Since the wiki performance was getting every more patchy, I have moved it from the 123-reg "Deluxe" shared hosting to a virtual private server.
It seems a bit better now, although it is currently getting lots of bot and crawler traffic as it is a new server.
We have set a max connection limit on the database server to save it getting overloaded - so you may see the occasional DB error, but a retry will usually fix it. (will remove that at some point
It has been upgraded to Mediawiki version 1.44 so it may look cosmetically different in places. Things like syntax highlighting of code shown in articles also now works.