Welcome to the OC
You haven't actually stated how much you are losing.
For example, I have had my '05 DE from new, serviced every 3k miles, never ragged from cold, yet about 8-10 years ago started to see some oil consumption.
On a 500mile motorway trip, I'd see about 250ml being used.
This is with Castrol Edge 5w30.
I don't however have a catch can yet.
My garage has checked and said no leaks and emissions are fine.
So I just continue to check often and never let it drop below half way from min to max.