Thanks both. I was more worried about the filter than the oil as I was thinking a bigger filter might have more oil inside it so less pressure or less oil in the engine as a result.
I will put it down to experience and stop worrying about it - but I will check everything in future. I can't be bothered trekking back to the place that did it as I don't suppose they've still got my oil filter cover - a guide I found said there should be one but not on mine there isn't, there's no room for it!
Is there any risk in adding the new fully synthetic 10w60 to whatever's left behind of the part-synthetic Magnatec after I've drained it as best as I can?
Last edited by jbb156; 14-04-13 at 16:51.
Reason: Thanks to both of you