To those that are saying if you don't use the packing service you will have to source your own packing boxes, materials etc - not necessarily. We have bought and sold six/seven times and have always preferred to pack our house contents ourselves and since we've graduated from hiring a van (the last four times) as we have waaaay too much stuff, our removers gave always provided everything we've needed (boxes, paper, bubble wrap, tape) as part of the deal.
Our last move (two weeks ago) we only had forty eight hours between exchange/booking the removal co and them collecting our first batch of boxes and furniture (our move was spread over five days as we seriously do have shed loads of things, lol, three days to load and two to unload 200 miles away), yet we managed to get around forty boxes packed in readiness - out of a total of 150+ - for them. We also assisted with export wrapping some of our more fragile/precious furniture items.
Our move cost nearly £4k (quotes ranged from £3400 - £4200) and god only knows how much extra they'd have charged to pack, but even had the cost of packing been included, I'm afraid I still wouldn't have wanted them to do it.....but that's just me being anal, lol!
When DS was tiny (six weeks) we moved ourselves in a hire van and next time (he was then about five) had a large nationwide removal co, but still opted to pack our own stuff......think if I wasn't so fussy/didn't have irreplaceable things I might consider packers if I had young DC....