http://www.amazon.co.uk/INTERLOCKING...4408678&sr=8-2
Perhaps you wanted that size specificially, but grids in the above link (for the shoe rack) are only 7" (185mm), only about half of the regular standard grid which is 14" (35cm).
I have a list of possible material sources (at least 20) for UK if anyone would like it. Email me at
cccages@aol.com. Not sure if it's up to date, but I add to it every now and then when someone finds grids in UK.