Is this a likely explanation?

[philcerbera]

A small puddle of oil has appeared between the front wheels overnight on the garage floor (4.5 1998). Took a look under the bonnet and it looks as if the dip stick was loose and not locked in place. The oil seems to have escaped upwards past the dipstick and then downwards on to the plate below. Oil level and pressure seems normal. Is this likely to be the explanation or should I have it checked out?

[simonsparrow]

Sounds likely. The only thing you can do is monitor it for a few days now that you've put the dipstick back in its place.