lusklabs , there many ways of getting bees out of a chimney
1, if its a fresh swarm with no wax, lite a smokey fire in the grate and they will fly off somewhere else, as with modern fires they are removed or gas so drill a hole into the chimney but not the gas flue and push smoke into it
2. stick a big (1metre square net )bag over the chimney and catch the bees in to that and then remove them else where
3, chimney cleaning rods and a brush, becarful as what come down will not be happy
4 scafold to the roof remove chimney pot and reach inside
5 climb into loft and cut out several bricks to make an access point and work from there( did this one several weeks ago no fire places and no chimney roof access)
this with me or have we fell a sleep yet
if you can think of any more ways it just takes some side ways thinking thats all