Thanks for all the replies (Jesawdy - I'll reply to your other post here as well as this post is more active)
I do have a Briel (Artemis model) machine, and am currently using with Solis double basket. I've followed all the advice on here and it has helped but yeah I do still get a fair few grounds in the cup. When I used the Briel baskets (which are pressurised) I didn't get anything coming through at all unless I took the 'crema enhancers' out, then I had plenty come through.
My Briel basket has since broken though, so no going back - the screw holding the filter/enhancer together sheared off mid-brew

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I guess the basket could be responsible as it's not specifically designed for Briel, but the improvement in my espresso since ditching the pressurised Briel baskets has been pretty impressive so I'm loathe to go back!
DC