Chris,
I've bought a number of cymbidiums over the last few months and I always
repot them as follows: 1) ensure plant is moist and has been in a reasonably
warm environment for a few days at least 2) remove from pot and take off all
old compost (as much as possible) 3) remove any dead roots and prune them if
necessary and dust with cinnamon 4) put in clay pot with plenty of spare
room for roots 5) add inorganic semihydro mix - i use only clay granules of
up to 1 cm, 6) water, stand in clay or plastic saucer and keep fairly warm
for a few weeks 7) I then move to outside greenhouse before moving them
outside later in May. Initially I water from base. Some I put in hanging
baskets which they love.
Good luck,
David