Standard Everyman fare but with a few that still have me scratching my head (then perhaps you need to get a 16a and to 9a Bren - see what I did there 😀 Yes Bren, hilarious!).
Firstly I can't see how 8d or any part of it is an "undergarment".
13d - Other than the definition, "seconds" and "cheap in the extreme", I'm at a loss.
Lastly I can't see how 2d realates to "or 17"? There is a 13 letter word that begins with 2d, "romeo" and the next 3 letters that is "of or like a 1d" but that's as far as I get.
Maybe I'm just overtired.
Regardless, thanks to Everyman.
Stay safe:-)