Help Desire keeps suggesting other Network Operators

[Salty Wagyu]

I'm on an unlocked Desire using a T-Mobile SIM, and the other day I decided to try out a GiffGaff SIM to see how good Internet coverage was then went back to my T-Mobile SIM.

Since doing that, my Desire keeps suggesting other Network Operators when it loses the Cell signal. It never did this before and I don't know how to disable this behaviour.

It shows a list - T-Mobile (with a star), Vodaphone, Three, Orange, etc. If the cell signal comes back on in time this particular network selection screen will disappear, but it is annoying nonetheless.

My Mobile Network settings are:
Data Roaming: disabled
Network Operators: T-Mobile
Network Mode: GSM / WCDMA auto
Enable always-on Mobile Data: enabled

Access Point Names:
T-Mobile Internet
T-Mobile Broadband
T-Mobile PictureMessage
(same APNs as before I tested out giffgaff SIM)

Any ideas? For reference I used APN Backup and Restore during SIM switching, if this may have affected it somehow.

 

[Deleted User]

Go to mobile network settings and make sure it is on 'Automatic' not 'manual'

 

[Salty Wagyu]

Would that be under Network Operators > Select automatically (automatically select preferred network)?

 

[Deleted User]

Yes, thats it. See that will always automatically select the best network, whereas on manual you select T-Mobile but when the signal goes because it is manual it asks you to choose another network.