Okay, i have so far done two things.

One - I updated the firmware to the Beta one that is flying around these forums...

Two -I changed the APN from "three.co.uk" to "3internet" (I created a new profile).

And that seems to have enabled both FTP and FTPS

It seems to have stopped a large number of site errors.

And randomly bypassed the Three adult filters too.

Not sure what is going on currently. Will test more, but all very odd.

@Nevsie ,

Good news for the moment but which band do have you used to connect to 3 mobile operators?

@Robynbra 

Currently band 3 - why?
 

@Nevsie 

Band 1=?

Band 2=?

Only for understand better this new firmware!

Thanks

@Robynbra 

Happy to help, but what are you asking me to do?

Or information to provide?

I have tried basic - internet and enabling two bands. 

I have selected:

3,20

3,7

3,3

But under advanced - internet status... It only shows a single band, of 3, and 4G LTE never changed to LTE+

Is my SIM LTE only?

Is my nearest antenna band 3 only?

Three are meant to be LTE+....

@Nevsie, thanks for your answer and to share with me your thinking... 

According me is this firmware that try to add together the two bands to go ahead more quickly that the single band... 

I have tested the same like you have made.. But also to me my results are the same.. Only 3G.!

Try to not select band but try to make in auto selection... 

So return back and look where the modem found in automatic mode the network.. If you look well the router show the two bands... And after you will are able to block the two bands to not move the automatic mode to the router to find in continuos the network... 

Sorry but i have others problems with this modem... Are you able to see if in your modem the WiFi band grows up and down? 

And if you check the wifi range with some mobile app like "wifi analyzer" or others apps.. You see that come out this strange ghost 2.4 ghz network and after little time this network disappeared... look here:

http://www.imagebam.com/image/e365e91344909904

these news from you i need to understand if is fault of my modem or all these Archer MR600 have these problems.

Thanks 

Also to @Kevin_Z

is possible to receive an "official" answer abot this ghost network and about the wifi network that run up and down?

thanks