OK, after a week with the replacement phone I have had mixed experiences.
Battery life has been good. On a normal day I charge before going to bed, and then use the phone during the day for checking emails and news, listening to music, 1 or 2 calls and sometimes a 15 minute gaming session at lunch. I have been showing 45-50% remaining when I stick it on charge in the evening. This is pretty good, I think, especially as I have WiFi and Bluetooth on at all times.
At the weekend I went to London for the match and by 6PM as I was down to 20% but I had used Maps and taken quite a few photos, uploading some to Facebook plus a few calls and quite a bit of browsing too. Again not bad at all.
Connectivity in the main has been more reliable BUT the phone lost signal a few times yesterday and then locked up completely, requiring a hard reboot to get things going again. I wonder if my sim card is playing up (it is nearly 2 years old) - I have ordered a replacement just in case. Notwithstanding that, I am rather unimpressed that the device can lock up in this manner. I've just noticed that I have no signal again as I write this. Ah, back again.
I am sad that these issues (connectivity and freezing) are causing me to question the wisdom of my switch. If I could find an Android device that could get somewhere near my particular requirements I am afraid that my Lumia would find itself on Ebay.
Maybe the new sim will help. Maybe Windows 8.1 will blow me away. Here's hoping.