When I moved back to the UK last April I looked into the cheapest way of doing this...
And discovered that it was to send the items with the Swiss Post Office.
I packed the items up and weighed the boxes at home, and used the online form to create the 'waybill' (you can find it here: https://www.post.ch/en/private/sendi...arcels-private
I then took the boxes into the post office, they weighed them, checked the waybill and then I paid for the postage. On one occasion my parcel was slightly heavier than I thought and we had to create a new waybill because it had tipped over onto a different price bracket... but apart from that it went very smoothly.
I didn't have to pay any customs fees either, although that was probably because the value of the goods was not that high.