We use Royal Mail for plastic and FedEx / DPD.
UK:
For the plastic containers, this will be Royal Mail £1.99.
For the glass containers, this will be £2.99 48 hours tracked and signed for DPD/FEDEX.
For the glass containers, this will be £3.99 next day delivery.
International, tracked and signed:
Europe
6-7 days
0 - 1000g £15.93
1001 - 2000g: £17.28
Australia Standard Parcel:
6-7 days
0 - 1000g £23.25
1001 - 2000g: £32.15
Canada and the US
6-7 days
0 - 1000g £19.75
1001 - 2000g: £26.13