I'm told they'll be functioning for quite a few months yet as potential developers can't get the access they need along the far end of the High St and the developers of the adjoining site are unwilling to allow access that way (perhaps hoping to drive down the price for the Manor site???)
Their stock hasn't diminished at all - increased if anything. I'd say. So keep supporting them as long as they're there!
Given what drunclejohn states is correct and the presence of other developments in the area would it not be appropriate for Manor Nurseries to issue a statement refuting rumours that they are closing or even selling shortly.