TG582n Router updated now connection is poor

[#1]

My TG582n router firmware has been updated to 10.2.5.2.FO- I'm presuming by PlusNet as I didn't do it, or request it - and now when browsing the web, pages are intermittently timing out or loading with missing images/videos.
I also use it to connect remotely to work servers and SQL servers and that is now taking several attempts to do so. Once a connection is made, it usually stays live however.
I only noticed the router had been upgraded when Destiny on the PS4 (on LAN) complained about a NAT type 3. When I went on the router, the password had been reset to the standard one and the firmware had been updated.
The internet connection itself seems solid and using LAN appears to be fine so it would seem to be wireless that has become an issue since the firmware was changed.
I'm not sure what could have changed with regards to wireless - I set it back to manual channel 13 from automatic as it was before. (Everyone around here is engaged in "Router Warfare" and my little TG582n is a bit underpowered. I'm now trying channel 10.)
Is there anything PlusNet can see that is flagging any issues or is there a way I can have it rolled back please, as it was working fine?

[#2]

Are you sure it's a wireless problem, and not a problem with the router's DNS server - see this thread: https://community.plus.net/forum/index.php/topic,148555.0.html
In theory, it's better to be on the same channel as other routers, rather than a nearby channel that partly overlaps. Because the channels on the 2.4 GHz band are 20 MHz wide, but spaced 5 MHz apart, that generally leaves three non-overlapping channels to stick to, 1, 6 and 11. See https://en.wikipedia.org/wiki/List_of_WLAN_channels

[#3]

Thanks  :). I'll give the Google DNS a try. Didn't cross my mind as the ninja firmware update seemed rather coincidental and put me off checking for a bad DNS.
I've put it back to automatic channel settings now. It picked 11.

[#4]

Yep... That'll be me then! Time to break out TelNet.
Many thanks.

[#5]

I would sooner that PlusNet did it for us.
John

[#6]

I'm not so sure it's not down to the firmware. I'm getting the similar issues, although getting timeouts to various sites on wired LAN, and while checking the router I also noticed I have been updated to 10.2.5.2.FO (TG582n FTTC).
I'm getting intermittent issues. PlusNet's sites respond fast, others are variable, sometimes working, sometimes not. Many part load or just not at all. Reboot PC and works okay for a bit, though could be coincidence, then stops.
I'll try changing DNS server settings, though I don't like depending on a public DNS outside of the ISP.
If that fixes it, it's easy to jump to the conclusion PN's DNS servers at fault, and maybe they are, but seems suspect that it started with the firmware update.
Out of interest with the forced firmware update I need to recheck some old DNS resolution issues that are down to the router and were causing issues with my mail server - https://community.plus.net/forum/index.php/topic,145091.0/topicseen.html

[#7]

You could configure your computer to use the Plusnet DNS servers (212.159.6.9 and 212.159.6.10) directly, bypassing the DNS server in the router. It's even possible to re-configure the router to assign the DNS servers like that - method 2 from http://npr.me.uk/changedns.html

[#8]

Good idea, although doing that or even just changing DNS on your own PC to those or Google's is going to cause loss of internal DNS resolution I think? You might get away with it with Windows devices as they may use WINS and an elected master browser, but if I want to access non Windows devices that have registered their name on the router DNS, then I would no longer be able to.

[#9]

I think the main fix is just setting dns server config WANDownSpoofing=disabled

[#10]

Moderator Note
Thread locked.
Please refer to this topic http://community.plus.net/forum/index.php/topic,148555.0.html