Instead of topping it up, I thought it would be better to just change the oil again. I filled it last time with exactly 800ml of 10w30, when iI measured what came out it was 700ml

I always change the oil half way between services (1250 after the last service) , I now have exactly 7000ml on the clock which means it's used 100ml of oil in 750 miles.
I can't see where it's gone - there are no obvious leaks or stains and there is never any oil on the garage floor.
Normally I don't bother cleaning the oil strainer, leaving this for the dealer to do when it gets serviced. However, I've just taken it out and there is what I think is a lot of swarf, several thin slivers of about 1mm in length on the strainer, on the spring and in the bowl behind the nut (if you know what I mean). Is this normal? I'm used to doing car maintenance where you just change the oil and chuck the old filter away - you can't see what's inside.
As to where the oil went, I have no idea. The coolant is clean, so no cylinder head gasket probs. It's never used one drop of oil before.
