Thanks No84, I'm just hoping I don't go back to struggling again tmrw, time will tell.
Welcome to the fold S88, hope the injury isn't too bad and you're able to join us soon.
LL, there are a number of ways you can find your max. You can find a hill of 100-200 m and run up it 4 or 5 times. After each rep jog down slowly and increase the effort on the next run up until you go flat out on your last rep. Another way would be to run a hard 800m rest for a short while and then do a flat out 400m, the number you see after your last rep will be pretty close to your max. You might want hubby with you in case you collapse in a pile, or if their is a malfunction with the hrm he can take your hr manually
I started this training before I got my hrm and I was just trying to run nice and easy. When I got my hrm I realised that my nice easy runs had been run at about 82% or so. Just try and keep the runs really easy, conversation pace. When you are done you shouldn't be out of breath at all. Obviously the better shape you're in, the better your pace will be, but I don't think i've read of anyone who hasn't had to slow down considerably for this appoach to training.
As far as hrm go, If you don't need/want a hrm with all the bells and whistles then you can get some very basic models pretty cheap(£20ish but no idea about the quality.) I got a garmin fr50, which I've been really happy with, for £44, and it does everything I need, plus it auto downloads the info straight to your computer when you get within a few metres of your computer. There is an optional foot pod that you can get with it that will tell you distance and pace but that's an extra £60, well out of my price range at this moment in time. You can have a look at heartratemonitor.co.uk if you want to look at diff models and prices. I'm sure there are plenty of other places, but it's worth having a look there cos I think they have pretty decent prices and you can at least get an idea of price ranges,etc. Hope santa doesn't forget you 
Happy basing to all.