Blackberry and Apple Jelly

Following this recipe that I found via google:

I made some blackberry and apple jelly with blackberries that we picked last month, and some of Mum & Dad's large amount of cooking apples. The only variation being that for the first half I ran out of caster sugar and had to use some cinnamon caster sugar as well, so that'll be interesting to see how it turns out.

The other thing is that I think I used too much water in the initial simmering stage, so I ended up having to boil the whole lot for about 15 minutes, rather than 8.