All them landrovers use 16" that i seen, them you mention are to fit fronera/maverick/gay lander etc..
And its 16 inch tyres he's on about!
The 225's are 29.3 inch tall (Diameter)
whereas 235.70.16's (pretty much a standard size on Discovery's) are 29 inch tall.
So what you are looking at is tyres that are a bit narrower, but ever so slightly taller (0.3 inch)
They are a Landrover fitment for many early 90's.