I already sell items that go in small envelopes and postage for those has worked.
I am doing something wrong as I cannot get the parcel sized items to show parcel sized prices, only large letter size prices.
I have the same problem with every postage option so if anyone could help I would really appreciate it. I am hoping the pictures will show what I have done as I am not very good at explaining.
Settings in Data

Settings in Options

Settings in Royal Mail shipping

What the customer sees (70.00 refers to gms)

PS cannot upgrade to 2 as my theme does not yet support it.