Just to correct a major point here - RM is FINE for anything from 1st class upwards but the rules on parcel sizes mean you can only send pistols:
https://personal.help.royalmail.com/...detail/a_id/94
http://www.royalmail.com/sites/defau...naury-2017.pdf
The terms and conditions have been updated since I checked last year as they had been superseded by the online list, this has now been corrected. What IS of paramount importance is that you NEVER use the leaflet in the Post Office as the old one is well out of date and contains incorrect advice and
the updated one STILL hasn't been corrected.
And, as implied, ALWAYS check online as the T&C's state that is the definitive list.