I'm noticing better charging behavior. I listen to music over a bluetooth headset and despite the V5 being plugged in to a regular ~5 Watt USB port on my workstation (not high power), I would see the battery levels descend to around 50%. Not sure if the battery levels were *really* that low but it was surprising. The V5 would charge to 100% overnight w/the included high-power charger.
With the new ROM the V5 appears to stay fully charged while plugged into the workstation and listening to music over Bluetooth.
Yes, the Bluetooth GPS app lets you pair an external BT GPS. You have to enable "Allow Mock Locations" in the Developer options. You can then keep the V5's GPS disabled and the Android location API will use the external GPS. There are other similar external GPS apps in the Play Store.
I tried it last weekend with an old Garmin GPS 10x. Apparently the Garmin uses the SiRF Star III chipset. It locks on very fast. The V5's LED lights up solid blue when connected to the external GPS.
The "GPS Test" app that everyone uses will show whether you have a GPS lock, etc. but doesn't show the signal strength bars. However, you can see all the GPS signal details and logging inside the Bluetooth GPS app. Bluetooth GPS also comes with a widget that shows signal strength, etc.
Regular location apps like Maps work seamlessly with the external GPS.
I can select camera, video or panorama mode. I didn't do anything special in the install. Perhaps it's a matter of getting the proper .apk? I saw some other .apks that were smaller or were packed as .zip's. The link I included above is the one I used and was a simple install once the existing Gallery2.* was renamed (or removed).
Odd, it was not an option in the Camera app on my V5 running the latest stock ROM. I think 6mp was the highest selectable resolution despite the "Hardware Info" app showing that 8mp was supported by the camera module.
If there aren't two entries for 3 UK at slots 0 and 1 -- WCDMA and then GSM -- then that seems like it could be your problem, no? All I know is that AT&T occupies the top two slots in my V5's list followed by many historical networks that were acquired or renamed by AT&T over the years. I haven't seen an "R" yet. I think all that info is supposed to be baked into your SIM card and you shouldn't have to be entering it manually.
FYI, the concatenated MCC/MNC for Hutchison (3) is like: 23420 - Hutchinson 3G (3) - United Kingdom
It sounds like you're more interested in making sure roaming doesn't happen at all but if you're just interested in squelching the warnings and indicators then the Gravity Box app has two settings related to roaming: "Disable roaming warnings: Disables roaming warnings when sending messages or making phone calls while roaming." "Disable roaming indicators: When disabled, R indicator will not be visible while roaming. Use with caution."