@Keane  Thanks for the post, it does sound like a battery is needed here.
Also - to optimize performance, make sure to give the filter a good wash and checked for any partially blocked airways:

1. Please load up and follow along with this vide: "checking-for-blockages"

http://ms.spr.ly/6181bUgMh

2. Then please check the bin inlet

In the inlet the wand connects to the clear bin there is a tiny flap. Tilt the machine up and down while looking into the inlet. Does the flap open and close freely? If it's stuck, please remove and wash the bin and poke it with your finger until it moves freely. Make sure the bin is 100 percent dry before putting it back on.

This video can guide you in removing the bin:

http://ms.spr.ly/6186bUg3E

Thanks Adam for your advice.

Have recently washed filters and will check what you suggested re blockages and the bin flap.

thanks again