Will the plants be safe enough in the post?

With regard to how the plants are packaged and sent: Plants are packed in specially made boxes (so the pots fit perfectly). The pots are sealed and are held in position within the box to prevent damage, - even if transported upside down. I've sent many hundreds of them and had no problems yet with this packaging method. 

The plants are guaranteed to arrive healthy and viable.

From sending, UK deliveries usually arrive next day, if not, the day after. If I receive payments near the weekend, then, rather than post on a Friday (or Saturday), I usually wait until Monday, to avoid the potential Sunday 'in limbo'. But recipient can override this and I can send as soon as.

By default, plants are sent using Royal Mail recorded delivery (but I can simply send standard first class at the recipient's request, if you donít want to sign for it).

EU deliveries are typically posted on a Monday and typically take a few days longer but usually arrive within the week of sending. The longest delivery was to Turkey, which took 11 days, but the plants survived okay.

Having said that the plants are as well packed as they can be, don't be too surprised if they lose a leaf or two during transport.  

Plants may even (though by no means always) drop one or two more leaves after you've received them, don't worry too much if this happens either. The plants know what they're doing; they will be adapting to their new environment.