New to Plusnet. Lots of dropouts.
Hi, I'm not sure if this will help as such but this is the exact same problems I've been having with mine and mine also at those times which was also always fine during the day too (apart from I did have a couple of Sunday's which were bad). This has been since around Christmas time for me that I've had this happen.
I had an engineer come out who tested the the line, router and also my wire that goes from the master socket to the router as I do have a direct wire going to my master socket (which is a really good expensive one too) which he tested for me direct into his box and said was fantastic however we did another test with Plusnet by using their shorter wire and they noticed a difference so it has been confusing for me because it has only been since around Christmas time this started and it's only at those times it happens for me too which baffles me. I'm going to have to move the master socket I think which will cost me £160 and I just hope this fixes the problem as I can then use the short Plusnet wire into the master socket then and at least eliminate that possibility, it's just a lot of money to do.
But I also have the same exact things you mentioned there and at those times too which is weird as it's completely fine otherwise and sometimes I've had 11 days of solid connection until it starts again.
I know this might not have been the biggest help but I hope it's given you some insight to a degree as I've also been having the same exact thing and it's always around those hours too.
Hope this helped a little 
Yeah @oldbondstreet I've said it so many times before but this is a case of how we are so behind the times with the infrastructure here, we are like 35th behind in the world now and that's because as we had the internet fairly on we never upgraded or updated our infrastructure so now most of us are on the old Fibre to the Cabinet system which is basically fibre optic wires going to the cabinets from the exchange then to our house the old copper wiring which are forever breaking, causing problems, slowing down speeds, noise on the line etc.. it's ridiculous but it's not even the Plusnet (or the ISP's) fault because they need to be upgraded.
We should be on Fibre to the Premises at least now which is basically the fibre optic wires direct from the exchange to our homes with no cabinet in between and no old ageing copper wiring under the ground delivering our internet.
Have a look at this here:
There's more on this here as well as a FTTP checker to see if they have any plans to upgrade your area: https://www.openreach.com/fibre-broadband/fibre-first
I've spoken to BT and various ISP's a lot about this and apparently they are working hard to get it fully covered but a lot of places aren't done or do they say they have plans to but it really is a necessity now because it's not going to be long where it can't keep up with technology.
It's something that needs to be done and this will help us and the ISP's as it's not actually their fault a lot of the time but the infrastructure which BT Openreach have to upgrade.
Hope this helps
I don't think it's to do with that @wylesshaun as mines been since before Christmas.
I'm going to move my master socket as soon as I can afford to as that should eliminate things for me or at least rule out the possibility of this as it's been so conflicting and a lot of it is a guessing game however as mentioned above is what we need now more than anything.
I've had so many conversations about this with ISP's and engineers, the one who came out to me a couple of weeks ago said himself once this is done it'll solve half of the problems and give people a more consistent, solid and faster internet.
What we have in the UK for these premium packages are standard in lots of places such as Egypt and South Korea I believe and many others.
We'll get there eventually but I know when you put in the FTTP checker on the BT Openreach site I linked in the post above if they say they have no plans for your area they want you to drum up support in your community and contribute to funds to go towards it for them to do it however the engineer told me they do plan to do them eventually anyway, they have no choice because they are playing catch up.
It's this here which we need.
The sooner it's done the better as we'll have less problems at least, not saying it will be perfect but it'll be much better than what it is now which is why no matter which ISP you go to you tend to have problems at some point along the lines and it's usually due to this which is not even a fault of the ISP's either.
You're welcome, it's the same for me, says they have no plans to do my area however the engineer told me that they do and will be doing so I think it's just a case of being patient.
It does need to be done though, we shouldn't have these problems we have with the internet at the moment to the level which we do but as I say it's not even Plusnet or the ISP's fault most of the time, it's usually an issue due to this but the ISP's are the one's who get the stick for it at times.
Hopefully they'll do it soon, we need to be up to date with things not behind the way we are at the moment.
It'll be better for them too cause the amount of call out's and engineer visits BT Openreach are forever having to do could also be limited too with a better more up to date infrastructure which we should have anyway.
Guess we're just going to have to be patient however you're welcome in regards to the description