If you need to re-establish your H3 MMS settings there are two distinct methods.
1. Perform a factory reset on your handset (this
is destructive to your content, contacts etc..

)
2. Perform the following script (this is
not destructive
)
APN Settings (Menu 9 5 1)
Connection Title = 3
Bearer = UMTS
Username =
Password =
APN = three.co.uk
MMS Centre (Menu 1 8 2 6)
Title = Multimedia message
MMSC URL = http://mms.um.three.co.uk:10021/mmsc
MMS Proxy = mms.three.co.uk:8799
Connection Mode = TCP
Access point = 3
Browser Settings (Menu 6 6 1)
Service name = 3 Services
Homepage = http://mobile.three.co.uk/hb/lg/HutchKey
Connection mode = TCP without Proxy
Security = NonSecure
Timeout = 150
Access point = 3