250/1 oil drain plug

Silly question but where is the oil drain plug on a ts250/1 ? Haynes manual says it's inclined plug but mine's got 2 flat bolts. Looking from the front on the left side (exhaust side) there's a 22mm head bolt and slightly behind and on the gearleaver side a 17mm head bolt and I know I don't want to undo the wrong one ! 
