I've not heard of them but check with the RYA directly to ensure they are RYA approved. They should also be able to give you more information about the company. Their certification hotline number is (UK) 023 8060 4158 or email@example.com
Jolly parrot are based in Gibraltar, at Queensway quay. We were moored next to a couple of their boats on different occasions. No alarms raised ..seemed a kosher firm, customers seemed happy enough, no crashes to report - which for some charter businesses would be a ringing endorsement!