Deleting GPRS settings in 9300

It's been a long day, and I don't usually have too much of a problem setting
up MMS...

The situation. I've an unlocked (once T-Mobile) 9300 on Virgin in the UK.
After having several sims in it over the past I decided to delete all GPRS
and MMS accounts and start again. So, I went on to the Virgin site and got
'picture message' configuration SMS shoved to my phone.

First, I was surprised to get two sets of GPRS settings sent for MMS (and
no, that doesn't include the 'virgin enhanced' settings). Are they send and
receive? If so, I haven't yet found out how to make the MMS settings use
them, but that's by the by..

Second, the settings stored were named Picture Message(m) and Picture
Message(n), where n and m are obviously to eliminate duplicates. If I delete
these accounts and reinstall I get Picture Message (o) and Picture
Message(p), where o and p are m+2 and n+2. In other words, it has somehow
retained a memory of the 'deleted' accounts, and will not let me reuse the
names. Whay? How do I permanently delete them?

Finally, the account called Picture Message(3) is marked as read-only, so I
cannot delete or edit it. How did that happen?