Hi Brendan, I have the same words, (I think), with 7d being a hypothetical unit of memory rather than a device.
7d. is a famous captain in an abb. for Merchant Navy
28a. is a 3-letter word for something that collects dung + a word for a container that holds bleach.
6a..I'm not sure. The first 3 letters come up as an order on Google, but not in my 13th. ed. Chambers.
'one' can be A, but if it's an anagram of 'tea', then the indicator is missing. Perhaps there is a different explanation.