Intermittent Fibre connection

Hi there, I've just joined the site.
I've had SKY Fibre unlimited since I moved into my property in December 2018. For the first few weeks, connectivity was perfect - no dropouts, pretty good speeds. From around the start of February 2019, I have had major intermittency issues. BT/Openreach have attended on numerous occasions, thinking they have isolated the fault on every occasion (ranging from dodgy connectors at the cabinet to overhanging branches on nearby overhead cables). Eight weeks on and I am still in the same situation. Sky contacted me yesterday and basically washed their hands of it, stating that "everything has been tried" and no more can be done (obviously on the advise of BT). I am at my wits end with this and feel completely shafted.
Can anyone give me any advice as to what to do next or any advice as how to nail this down? I should advise that I am not a network techy, just an end user trying to get to the bottom of this problem and feeling abandoned.

Thanks in advance, Lee.

When you say intermittent issues do you actually mean the Sky Hub is dropping the connection and spending a minute or so reconnecting? Or just the simplistic the Internet is broken.

For anyone to help the connection statistics need digging out from the Sky Hub, and its worth adding if this is a Sky Q hub that buying your own modem to sit in front might improve stability.

Andrew, thanks for replying. Yes, the hub is dropping connection completely, periodically. No set pattern that I can find. On every occasion, the connection is regained relatively quickly. Lee.