Can I suggest Rose, that you use apples for your pectin with rowan berries, cooking apples like Bramleys have pectin.

Quantity ratio - rowan 4 : 3 apples. (say, 4 pounds rowan to 3 pounds Bramleys), cooked up for 20 minutes or so - till soft.

Sugar - 1 pound for every 1 pint of juice after cooking up the fruit.

When I have Bramleys and use them for say, apple pie or crumble, I cook up the peel and cores, strain and freeze the liquid as reserve pectin when making other preserves with less pectin.

Hope this helps.

Good luck!