Not tried them but if there not production line crap, they should be good, though I am addicted to cheery bakewell flapjack the local spar sells. I think there made by Dorset flapjacks.
I’ve always struggle to make a good flapjack, that didn’t turn into a nice granola but Hughs peanut boost bars are pretty damned good, they may not quite fall into the purists “flapjack” criteria. Ignore the instruction to use 150g of seeds or fruit, & put both in!
P.S Grum: That website link has an “Important notice Please note that the shop is temporarily closed as we are having a break from making flapjack for a few weeks.” hense why we might not get chance to try them…