Help Please

I am running a mesh system using EAP265HD AP's that has been working fine with my 900meg BT broadband and giving me speeds of between 750 and 800meg I changed my broadband provider to sky yesterday and now have Sky's 900meg fibre. The speeds i am getting if i connect direct to the router are around 800meg but if i connect to the mesh system those speeds drop to around 80meg. The only change has been the new router,I am using the same network cable from the router to the switchbox and the same cable from the switchbox to the first AP. 

I have tried disabling the wifi on the router in case they are conflicting but still can only get speeds around 80meg.

Can anyone advise me on the way forward to try and get my system back to somewhere close to what it was.

Thank You