Thanks to everyone for your kind words and commiserations. Maisie was rapidly becoming a community cat and wouldn't need an invitation to go into Dave and Lucie or Nick and Val's so they will be missing her too. I feel certain I wasn't the only one to shed a tear or two. 
I've never known a cat that purred or meowed as much as Maisie - what a sweetie she was. Who will I say goodnight to now...