Hi Paul,
I got the chequer plate for Shemarah from Kit Form Services. They do a range of patterns but all nominally 1:24 scale. It might not look too bad on a 1:48 scale model. (**LINK**)
I tried the Slaters Plasticard version but either they sent the wrong size or I ordered the wrong part number and the sheet that I received was much too coarse a pattern, probably around 1:6 or thereabouts. I did not send it back, just stuck it in my might come in useful one day box.
There is a Chinese company call Lion Roar who make a vast range of superdetailing parts and they do several photo etched brass sheets but I think the nearest scale to yours would be 1:35 They use the description anti skid plate if you want to search for a supplier.
The photo etched brass version has the advantage over plastic in that it can be bent round very tight corners by scoring it and then folding it over a sharp edge like a steel rule.
Regards
Gareth