I've got a washing maching machine connected to a waste pipe via a
standpipe and p-trap.

I've now purchased a dishwasher and would like to connect the waste
from the dishwasher to the existing arrangement by replacing the p-trap
with an appliance nozzle trap.

Here's a link to a picture of an appliance nozzle trap:

http://www.wickes.co.uk/invt/431942

I'll connect the waste hose from the dishwasher to the spigot on the
appliance nozzle trap.

But I'm a complete novice when it comes to plumbing, so my my question
is: can you think of any reason why this arrangement might be a bad
idea ?

I would appreciate any comments.