McG: you didn't say whether you actually used a bookmark (favourite) to get mudcat, but if you do...

In Safari, tap the book icon at the top - you get a sidebar (column on left).
If the sidebar book icon is not selected. tap it to see bookmarks.
Find the mudcat bookmark. If you put it along the top of the screen, tap 'Favourites'. If you put it in a folder, tap that. Repeat until you find it.
Once you can see it, tap 'Edit' at the bottom of the sidebar.
Tap the mudcat bookmark. You can then edit its name and URL.
Check the URL is exactly http://mudcat.org - if not edit it.
Tap 'Done' on the keyboard.
Tap 'Done' at the bottom of the sidebar.

(That longwinded procedure is an Apple mandatory standard - you'll find it in other apps.)

If you change to Firefox for iOS I'd be interested in what you think of it.