You must really be a glutton for punishment if you want to do crosswords you don't even have :-)
but here goes....5 dn answer is "ships", 18 dn clue is "5 singularly: space one " (6)
Letters in are E-B-R-.
To Gordibhoy, Some of us are not gluttons for punishment but are happy to test our wits and in the process help others. What a pity John (from Arran's) efforts seem to have been in vain.