engineers square - recommendations

Gents,

I'm currently looking for an engineers square to add to my tool collection. I'll be squaring up some plates soon and I believe an engineers square would be rather useful to have. I've googled a bit, but there's seems to be a limited amount of mid shelf / reasonable monies (<£200) squares available. Ebay has loads of old ones for grabs, but there's no guarantee any of them are actually close to being square. New ones, like M&W, seem to be happily made in China, without even a note on what specs they've been done to, just mentions DIN 875, but whether it's 0, 1 or 5000 no one knows (or I'm shite at searching). I'd be happy with 200mm or smth close, doesn't have to be new, can be used (probably better as stuff was better years ago) as long as it's, well, square.

Any help is appreciated.

Regards,
dsc.