Oh dear! That sounds rather nightmarish. I think it depends on how much they are doing for you. If they’ve quoted to pack for you, this usually would include packing materials but you need to check your t’s and c’s.
Our most recent move - with full packing included - the movers supplied everything. They happily used original boxes where we had them, but they built their own boxes if we didn’t. Depending on the insurance value or weight, a couple of things needed wooden crates. They asked about these specifically ahead of time and took measurements etc so they arrived with the correct sized crate. they were a big company and clearly ready for anything that could - and did - pop up unexpectedly on the day. They were pointing out things we’d forgotten like the bike rack which was still attached to the car! but they didn’t charge more to pack those extra bits.
The move before that, we packed ourselves . They just loaded the boxes and furniture onto the lorries. If we didn’t have the original box for stuff like electronics, we ended up carting it there ourselves - TV wrapped in a duvet in the back of the car. The movers would have boxed it for us if we had asked but there would have been a charge. As it’s only a mile, any chance you would be happy to move the electronics yourself? I know it defeats the point of using movers but we thought the extra packing cost didn’t offer value for money in that case. Big mirrors, framed pictures - they wrapped in blankets and loaded carefully, but we only had 2 or 3. But the smaller pictures and things, I wrapped and packed into boxes.
I did have to cancel a move a week before the date because the sale fell apart, but the movers were understanding and flexible. I did give them the heads up as soon as things seriously started to look like they were going sideways. Although it took us about a year to find another house, get the new sale through and move, they didn’t charge us a penny extra and said these things happen a lot. We had used them a couple of times before, and did use them we did eventually move, so maybe that had something to do with it. These movers were family run and local and have an excellent reputation. I can’t imagine that the bigger firm who did the full service move would be as lenient...
How likely is it that the house will be ready by the 15th? The new build we bought was about a week later than it was supposed to be (and by that I mean they handed over the keys a week later than the date they agreed to and that was over 3 months later than the estimate we were given when we bought it) and it wasn’t even finished then. Kitchen was incomplete, parts of the interior not decorated at all. In hindsight we should not have accepted the keys on the day and my advice to anyone buying a new build is to be fully prepared to reject it on the day if there are big things you aren’t happy with. If I could do it again, I would insist on a Second walk through before we complete and if there are still major items outstanding, then I just wouldn’t complete. Our builder was simply not motivated to sort things out later.
I would have a frank and open conversation about the move dates with your builder and explain the penalties you would have to pay if they are late and you have to reschedule. If need be, state that if they fail to give you adequate notice of any delay, you will have to look at passing along any additional costs you will incur. Check whatever builder/consumer code your builder is signed up to. If it’s one of the big firms, there is usually some indication of a time scale they have to commit to. As organisations, the consumer code things are a bit toothless, but it can be helpful to know what your builder should be doing as it puts them on the back foot if they are not. get EVERYTHING in writing.
Sorry - long post and a bit garbled. I’ve just realised I’ve moved a lot. 6 times in 12 years 😳 And I hope I haven’t alarmed you about the new build - it’s stuff I wish someone had told me.
Good luck!