Enough food for Ladybird larvae?

About 2 weeks ago I noticed our Cherry tree had a pretty bad aphid infestation (the black ones) - it looks like ants were farming them. I bought some Ladybird larvae and put them in the tree about 10 days ago, with a glue band to stop the ants getting up and they've done a great job cleaning it up, it's been like having my own army of mercenary insects!

My question is: now the larvae are effectively trapped up there by the glue band, will they have enough food to pupate into adults so they can fly off the tree? There must be 30-40 0f them on the small tree and all of the obviously visible aphids have been munched up at this early stage. They must be less than 2 weeks old, maybe just over 1cm long. It's my first time dealing with aphids so am worried they'll infest badly again if I help the larvae move elsewhere manually.

I'd love them to stay and protect the tree but don't want to force them to starve/turn cannibalistic. Is there a way to keep the tree safe whilst looking after my team's best interests?

Thanks!