28 across: Mutt lost head, beside itself (4, 4)

Here, mutt = cur, lost head = l and mutt lost head, beside itself = curl curl = beach. That beside itself is nice.

4 down: My tips for young: usurp right in beach shelter (2, 5)

I like this one because DA hid the direct clue so well. It’s tips for young = yg, beach shelter = brolly, usurp right in beach shelter = bolly and tips for yound: usurp right in beach shelter = by golly = my.

Update: Thanks to David, I can include the following clue in the Gold:

17 down: Tidied desperate ax? (8)

It’s exceptionally difficult, but exceptionally good. Here, desperate = in need and ax = aten (x as Roman numeral), and the synonym for desperate is then interpreted cryptically, meaning that desperate ax = in need aten = neatened = tidied.