Runner Bean Pickle

We have a glut of Runner Beans, our neighbours and friends have all been given green bundles recently and still we have more.
I have made runner bean pickle from a recipe I found on the internet.

Spiced Runner Bean Pickle.

2 lb (900 g) runner beans (weighed after trimming and slicing)

1½ lb (700 g) onions, chopped

1½ pints (850 ml) malt vinegar

1½ oz (40 g) cornflour

1 heaped tablespoon mustard powder

1 rounded tablespoon turmeric

8 oz (225 g) soft brown sugar

1 lb (450 g) demerara sugar

salt

Put the chopped onions into a preserving pan or large casserole or saucepan with 10 fl oz (275 ml) of the vinegar. Bring them up to simmering point and let them simmer gently for about 20 minutes or until the onions are soft. Meanwhile cook the sliced beans in boiling salted water for 5 minutes, then strain them in a colander and add to the onions.

Now in a small basin mix the cornflour, mustard and turmeric with a little of the remaining vinegar – enough to make a smooth paste – then add this paste to the onion mixture. Pour in the rest of the vinegar and simmer everything for 10 minutes. After that stir in both quantities of sugar until they dissolve and continue to simmer for a further 15 minutes. Then pot the pickle in warmed, sterilised jars, and seal and label when cold. Keep for at least a month before eating