Data txfr stops suddenly yet BTOR modem holds sync'd connection

[#1]

Funny one this.
Last 3-4 days our connection suddenly stops transferring data in the middle of loading a page, or any data transfer event e.g. Dropbox sync etc etc. The BTOR modem is sync'd & holding a connection, it just seems like PN servers stop passing data. This FTTC line has been perfect for over 12 months with good speed considering copper line length & distance to Cab.
Last couple of days rebooting the BTOR modem has 'forced' data transfer to restart, but this evening it stopped again, & a reboot was no help. I rang Tech CS @ got some muppet  (sorry 'un-plug micro filters' Ha Ha  ) who knew nothing about FTTC, BUT her running the usual line checks kicked it back into life again.
She was most unhelpful/un-educated on FTTC & said "these things happen" & she can't raise it as a fault, yet I know it is. I have raised an online support ticket in the hope that the fibre team could monitor my connection to see what's up.
Any help with this would be most appreciated as we live in the sticks & I work from home over the web & a VPN tunnel, even 4G hasn't made it here reliably yet.
Best Regards
Mike
P.S. It's not REIN, not line damage etc etc, been there done that & got several T-Shirts 

[#2]

If the line is hold sync and a reboot of the modem is resolving the issue, it could be a fault with the modem.
Do the disconnections below look like the times you rebooted/disconnected?

The tech support person you spoke to would have been asking you to do the standard checks (and fibre connections do use filters now as they are self-install), there is absolutely no reason to be rude.
I've tested your line and it's showing a potential issue at the VLAN, however this normally manifests itself as a slowdown not a complete lack of data transfer.

[#3]

I rebooted the modem Monday 28th 21:00 when data txfr stopped yes, didn't help. Txfr restarted 1hr later as CS agent did line check.
I can't say about Sunday 27th 04:00 - 08:30 as wasn't at home. 21:30 ish... I did reboot the BTOR modem as data txfr was lost, & this helped.
I haven't logged anything before this so difficult to say.
As to being rude, after being held on hold by a CS agent straight after taking the call, who admitted to not knowing what she was doing for 15 mins whilst she tried to find out what to do, you would be somewhat frustrated.
She admitted to not knowing what she was doing, and beyond this took 20mins to do the preliminary line checks which should take a very few minutes.
After 20 mins+ & my washer being blamed for the data txfr loss, I have to say I was somewhat wound up. I politely asked her to pass the call to the fibre team, or a colleague with more experience she said it wasn't deemed a fault & I would have to put up with it!
NOT good Tech CS support in anybodies book - hence the 'muppet comment'
My support ticket has been updated to state that there 'is' an external issue being investigated, so there obviously is something awry.
Call me rude, maybe I was, BUT PN CS Tech training needs improving before putting such an agent on the front line to cause customer frustration!