I am a bit stuck.
10,11a In metal underwear, former Spice Girl stands in row (6,8)
For the second part I have ALGERINE - A LINE with GERI in it, which means a pirate. But there's no mention of a pirate.
29a ...The Northern urban change not to be considered a reversal in policy (9)
37d ...Hostage in Elsinore, covering eyes (4)
19d ...Bad for one at bottom of primeval loch... (3)
I also have two blank squares below TAUT and above CUSHY. I have spotted Tin Iron and Zinc and I've put in 50-26-30. I think I've got Mercury (MRCU so far) ... anyway, you can see I need a bit of help to finish it off!