You certainly need Chambers for these! I'll try not to give too much away.
For 10a, I assume you have the first 2 letters. Try Chambers with a ? in the 3rd position of the answer. One of the (more obscure) options should spring out and lead you to the letter you need. As I say, there's also a word in the clue that I've no idea about.
17 was one of my last letters. I knew what letter I needed it to be (from the letters before and after) so I played around with one of the words in the clue until Chambers confirmed one of them.
19 - you've got the answer so there's really only one word left which could give you your letter. Look up your answer in Chambers in relation to the word in the clue.
30 - Chambers 2nd definition should help
44 - Chambers 3rd definition should help
Hope those are 'vague' enough!