The issue was related to the means that the Poly used to detect a live mojo. The original poly needed to detect a specific voltage from the mojo, before switching on. If the poly was connected to a mojo with a newish battery, the mojo when switched on was able to build up to that specific voltage quickly, and the Poly switched on quickly. However if the mojo had an old battery that was past its best, the mojo would take longer to build up to that specific voltage, and it could take minutes for the Poly to switch on.
The solution was for Chord to modify the poly, so that it just needed to sense a voltage, rather than a specific voltage, and so even mojos with old batteries could quickly trigger the poly to wake up.
It sounds like you may have an early poly, plus an early mojo with an old battery. Your solution could be to fit a new battery in your mojo - best to email
support@chordelectronics.co.uk for confirmation of the best option for you.