I used my hermes. Was about £15 I think. Also paid about another £7 for insrance upto £300- saddle worth £350. Was worth it as saddle managed to get tree broken despite good pacaging! Did get £300 plus my postage back.
Will be following as also have a saddle to sell but when I asked my local Hermes collection point they said the box was too big, then sent one via Shutl (Ebay) and the drop off shop said he'd take it this time as the collection was due but they only usually take small parcels. Ive always found Parcel Force quotes to be much more than £20, I must be doing something wrong? The best Ive used in the past was Direct Courier Solutions, was about £15 and they used the major couriers like DPD who picked up the parcel. Was great with the job I used to have but I cant be in all day waiting anymore.
A professional saddler who sends a lot of saddles by post gave me a piece of advice if sending a saddle by post, and that was to use Parcelforce and no-one else! If using Hermes and/or Parcelmonkey (who are not couriers themselves, they contract out the service) then do read their customer reviews first - I remember a while ago on here someone used Hermes to send their lovely saddle and it was completely ruined.
Cheap and cheerful isn't always economic in the long run; and their insurance may very well not pay out if your saddle is ruined and/or lost.
I've just sent a very expensive dressage saddle and it cost £29.60 Royal Mail Special Delivery. Insured to £2500 and medium parcel (18" x 18" x 24"). Worse bit was dropping it off at the Post Office. My husband did it as a favour to me BUT was told by the jobsworth on the other side of the counter that the box was 1cm too big. He didn't know any better and therefore couldn't argue (whereas I would have having specifically bought a correctly sized box from a packing manufacturer!). So he was forced to cut the box down to size and tape it up again. Anyway - the saddle arrived on time (within 24 hours) and safely - that's the main thing.
I've sold about 6 in the last couple of years ranging from a nearly new Equipe Dressage worth £2K to others for around £3-400. I've always used Parcelforce and made sure that its well packaged with bubble wrap and other packing material, as well as photographing the packaging so that I have a record of the condition it left me in. I haven't often insured, I make it plain that if the buyer wants insurance above the level that comes with the standard package they pay extra for it.
Having said that I hand delivered the Equipe as it was only 30 miles away!
I've always used parcelforce through parcel2go. They work out about £9 for cheaper saddles and then £15 for expensive ones. Always arrive promptly and they have to accept them at the post office despite our local post office being the rudest most unhelpful people ever. Tracking number and insurance is good too