I've used Parcel2Go quite a lot, but recently I've usually ended up with boring old Parcel Force.
The problem with recommending a courier service is that people will say "NEVER use Courier X, use Courier Y" because they had one bad experience with X and none with Y, whereas someone else will have the exact opposite. They're all pretty good most of the time, and they all fvck up once in a while.
For packaging, I always keep the boxes when I buy stuff because I know it won't be long before I sell something! If you have a local music shop they usually dump boxes outside - the trick is finding out which days the rubbish is collected.