Inserting Downloaded Blocks at Correct Scale

Hopefully somebody can help me quickly as i have a deadline tomorrow and I'm quite stressed given that AutoCAD is still fairly new to me.

I am looking at how much space an office of lawyers would have if it moved in to one of my employer's properties.

I downloaded a block of a plan view of a wheelchair user so I can see just how much space there is available.

The block is dimensioned but when I insert it and measure its dimensions, the readings are different. For example, a dimension reads 1070mm but when I measure it, I get 1023mm. Not far out but when I measure a 150mm dimension, I get 83mm. A 460mm dimension is measured as 536mm.

INSUNITS = 0

I should add that when I measure up the original drawing of the wheelchair as it is as soon as I downloaded it, the measurements are wrong. Is it me or the drawing?

I would be most suspicious of the downloaded drawing.

Can you share the block or give a pointer as to where you downloaded it from?

Yeah, you got a bad block. It's probably a case of overwriting dimensions, if they even are dimensions. It should be an easy fix. If you can't fix it, someone here will be able to do that for you.

Thanks. The block was indeed bad, as I didn't have any problems with other blocks that I downloaded.