Need help with ASE server list address/routing

Running ASE on XBox, start as normal, select join, the unofficial pc server list is already selected and after around 5 seconds the list is populated. Or at least it used to be. As of last week it now takes consistently an additional two minutes. I tried everything and finally established it’s my ISP. I can reconnect my xbox via my phone hotspot or a neighbours router using different ISP everything is fine. I have tried talking to tech support and they aren’t convinced, as long as the connection from my router to their gateway is ok they say everything is fine.

I would like to establish the IP address to which the xbox game client connects after ‘join’ is selected in order to return the server list. Ie not the ip address for the nitrado network or the server I connect to, but the ip address or domain from which the server list is gotten.
 

Can anyone help or advise? 
 

Things were bad enough with five or six disconnects on every login but now a two minute wait with every the server list refresh makes the game nigh unplayable, some days taking half an hour just to get on.