Los Chimpos Ride Again

What on earth does 'horticultural worker' refer to?
You think it could mean a gardener, but then if it means somewhere like Kew Gardens it could mean anything; there are office workers, guides, the people who run and work in the Kew Garden bookshop, the photographers... the list is endless!

Where would a gardener meet a 'celestial orchestra'?
Does it mean a gardener in a graveyard somewhere, perhaps? But where?
There must be a hundred cemeteries in London and the outlying boroughs.

You roll your eyes and slump into your chair.

This is ridiculous!
There must be something you're missing...

You have 1 choice: