I don't claim to know, but would suggest contacting the buyer, preferably in writing, and saying that time was of the essence, or words to that affect, and if not collected by such and such a date you would be disposing of it and no longer accepting responsibility. I take it you have been paid ?
If you are looking for a definitive number of days or weeks in law you may be disappointed, it would need to be collected within a reasonable time if there is no express term in the contract (which will probably exist in verbal form). Reasonable is what a reasonable person would observe in this situation, in the famous words of Lord Devlin it would be the man on the Clapham Omnibus.
I do not think you are now risking a claim for negligence and would do as O_G says and contact the purchaser in writing.
Thanks everyone for yOur responses, sent a text and the person rang this morning and is coming this afternoon, I will keep my fingers crossed he turns up.
Sorry, we can't find any related questions. Try using the search bar at the top of the page to search for some keywords, or choose a topic and submit your own question.