I had packed it myself and added a letter detailing the story of the painting, the stimulus for it, where it had been exhibited etc and I waited rather apprehensively for news. BUT an email came in on the expected day saying :
The painting arrived at 16:00 this afternoon, safe and sound! What a masterful packing job!
Thank you so much for all of your help, and I know it will bring us many years of joy. Truly a beautiful piece.