Size of Sump Plug?

[robertp]

Went to do a quick oil change at weekend and found that I couldnt get socket on to the plug due to exhaust pipe. Going out to get a flat spanner so what size is it please? I'm guessing about 28mm but can someone confirm please?
Cheers
Robert

[shpub]

I use an adjustable...

[robertp]

Thanks Steve, but I've got a good source for reasonably priced tools and want to add it to my set, so once again, size anyone please?

[dlewis]

I bought a 29mm but it probably is 1 1/8" in old money.