Shaky VPN connection

[#1]

Hello, I have searched through the forum for answers to the problem I am experiencing but couldn't find anything. I hope someone here can help. I need to use VPN to connect to my server at work occasionally. I use a wi-fi connection. When I had the old broadband it worked perfectly. Since I switched to fibre optic the connection to the server at work drops after about 1-2 minutes. This does not happen if I connect my laptop to the router using an ethernet cable, so I guess the problem is the wi-fi. 

I read about wi-fi channels but could not find any actual instructions about checking/selecting a different channel, I dont even know whether it would help. I have a Plubnet Hub One router by the way.

Thank you for any help/suggestions

PS I have contacted Plusnet support chatline but they say no support for VPN issues 

[#2]

Sounds like the issue is not the VPN as you say it works via Cat5e.

Could be congestion on the wifi, I believe the hub one uses the same SSID for both 2.4 and 5Ghz channels, you may be connecting to 2.4GHz, if your device supports 5GHz I recommend connecting to that.

You need to change some settings on the router, instructions here:

http://www.plus.net/support/broadband/hardware/hub-one-user-guide.shtml

You have the option to seperate the wifi bands and give them different names.

FYI I have a VPN connection but it is via a Billion router.