Under the law these goods if left in your property come under abandoned goods, or the tort interference with goods act 1977. As with so much in law you are required to act reasonably, which you appear to have done leaving the goods there for so long, you may be liable for any damage to the goods whilst in your care so do not leave it any longer
You know your ex-husbands address write to him and say you wish the goods removed by ? date (say 2 months time), give him a means of gaining access by contacting you or another person, say you want them removed during daylight, (if this is the case, I assume you do not want it done at 3 in the morning) after which you will sell or dispose of them. If you do sell the goods return the money received to the owner of the goods.
If you want to be squeaky clean ask a local solicitor to write & send the letter on your behalf, they should not charge a lot and your ex-husband may take more notice.