I have a BM 7000. When I use a BL5000 or BL7000 the remote signal from the BM7000 comes straight away. However when I use a Beo4 (with AV button) remote, the remote signal from the BM7000 takes about 5 seconds. This causes the information on the BL7000 takes 5 seconds to update after giving a signal from the beo4 remote. Does anyone know if it is possible to get rid of this delay?

No it's not. The update happens immediately when using a 2-way remote, since the Beomaster knows that it needs to reply so that the remote knows the command went through. This doesn't happen with a Beo4 as the airspace needs to be kept free so to speak, and the Beomaster broadcasts a status update to all remotes at its own leisure some time later.