Recently installed UniFi AP - causes ‘jumping’ on Sky Q box

[jonnykerm2015]

I have just installed a UniFi Ubiquiti long range AP, and since doing so, when watching live tv or recorded programmes on Sky Q, the picture and audio 'jumps'.

Wi-Fi on Sky Q box is switched off, and it's connected to my Sky router via Ethernet through Powerline adapters. All worked fine before. Ubiquiti is cabled to Sky router.

Thanks in advance.