A tender for 21sqm - Seems a bit fishy. Is it somebody you work with often that's putting in the tender? If not I'd suspect they haven't got a clue and want you to price it all up, so they can then go in with a price themselves and spec that'd sort it out.
If it's nobody you've dealt with before, pinch the customer yourself and spec it properly and explain why. Tell them a price 3 times the one you're putting in and put them off lol