I assume you mean broad beans? Lol. Beads wouldn't do you much good!
Firstly, your 6.7 before dinner was too high. Generally speaking, our levels before evening meal are usually the lowest of the day as insulin resistance improves gradually as the day goes on.
Secondly, peas and beans, let alone a small potato, can raise levels. Peas and pulses are quite heavy on the old carbs compared with some vegetables. Some people can manage them, others can't.
Having said that, the actual rise was just under 2mmol/l. Could be better, could be worse.
Did you eat anything between finishing your lunch and taking your before dinner reading that might have caused the 6.7?