If you go the DC Kits website and select DCKITS DMU & EMU Kits then select DC Kits Plastic & Etched Detailing & Spares, or click on:
https://www.dckits-devideos.co.uk/index.php?route=product/category&path=131_167
then a large number of spares are listed including the ones you require, and they appear to be available for sale.
No connection with DC Kits, other than the fact I ordered some of the same spares (and other items) earlier this month. Haven't received them yet though, although we are still within the 28 days (just!) to be fair. Fingers crossed, as I also have my eye on the class 303 body kit which I have since noticed seems to be available too.