My T5 TDI 2.5 nearly always needs an oil top-up about a month before it's annual service, I know this because it annoys me to be putting good oil in only to be flushed away a few weeks later. It's done this for at least 10yrs, we do a modest mileage in it and it's still 'only' done about 130k which isn't much for these (our T4 had over 300k when we sold it).
About 2wks ago the oil light came on, this is after about 3k miles since service/MOT, on checking the dip stick was metal just a smear of what looked like old oil at the very bottom (below the low/high marks). My initial thought was that the garage forgot to change the oil or top up, they are adamant they did (perhaps a little too adamant, we all make mistakes!). They've looked it over and no leaks, there's noting on the drive and it doesn't seem to be smoking.
Any ideas? Does the oil change reset the service interval?