Thank you all for your replies and comments. Just a few observations:
Packaging is irrelevant. He has an on-site warranty. The repair tech will have no use for the packaging.
This is exactly how I saw it. When I purchased my ES110 I was told to keep the box incase anything went wrong and I would have to send it back. But with the Casio AP 710 and all their further high-end models they send someone out to you to repair it. I saw a video for Bonners Music which showed them delivering a large digital piano, unpacking it and disposing of the box. For large items you don't keep the box.
Unfortunately I think you'll have to live with it until things get back to normal.
Yep. I think that about sums it up. I have contacted Casio again but until the covid-19 issue is sorted they wont be able to send someone out - Which I fully understand.
Lesson learned as with any purchase, keep the packaging material for a while.
Casio has good service and they will fix your piano.
'
Still frustrating
Lesson most definitley learned. The most annoying aspect about this is that I photographed all the packaging as I took it out of the box, so if there was a fault I could put it all back in again in correct order. But of course the fault did not materialize for a few days. And again I can't emphasize how big the box was and how small my house is.
Where I went wrong in all this is failing to realise that if a fault did occur Casio would not be able to send someone out. So If I would of thought about it I guess I would of made space somehow for the box. Hindsight is such a wonderful thing.

I don't very often post on this forum, but do spend a lot of time browsing through it. I always find it pleasing how people take the time and effort to offer comments/remarks etc. And this post has been no exception. Again, thanks.