Simply use the code SHARE5 at the parcel hero checkout and get £5 off the cost of your shipment, whether you are a new customer or existing! Code can only be used once.
Also, thanks to ST3123 for the following:
"You can also get cashback with them at TCB and 5% off your first order (can't gaurantee the 5% will stack with this but the cashback might still work).
I find them the cheapest for MyHermes, starting at £2.63 for a small parcel up to 2KG..."