A further update...
After discovering that my battery is indeed ok, I have done a fresh installation of iOS7.1 and set it up as a new phone. I haven't downloaded any apps, set up any email accounts, or indeed loaded anything whatsoever onto the phone. All I have done is adjusted the settings to how I usually have them for battery saving purposes, and I have been browsing the internet for the last 2 hours to see what kind of battery life a phone with no apps or data loaded onto it will get. This for me is to rule out once and for all the 'conflicting' or 'compromised' apps possibility behind my battery drain. As no email accounts are loaded up either, no photos, nothing whatsoever, it must surely tell me what the problem is?
Not so :-(
My battery has possibly lasted an extra 10 minutes or so over the two hours of web browsing (my usual usage pattern). This amount is extremely negligible.
So it's not the battery, it isn't the apps, my phone isn't overheating, the location icon isn't on, the spinning wheel isn't on, there are no obvious hardware faults and yet my iPhone 5 still has dreadful battery life.
I'm truly stumped.