Thanks @JonHammIsMyJamm. It was hard because I did push myself a bit but it wasn't awful and wasn't in any discomfort. I only did my first 20 mins none stop last Friday and that was harder than this so I'm hoping it will get easier as I get fitter.
I guess main aims are:
Get leaner / more toned
Get fitter
Have nice time on my own with dog
Not aiming for races or anything but I do like to push myself. Would like to get a sub 30 min 5k.
I'm 37 and don't really do any exercise for the sake of exercise (before this) but I suppose fairly active. I only did my first run on the 12th May! Although a bit fat and old I did used to be very good at running when I was at school so I think there must be some kind of natural aptitude helping me along. Even then though I wouldn't really train and would just make myself do it but nearly die! So this is definitely the most enjoyable I've found running.