Suggestions please - pairing a charcoal sport coat.

So I picked up this jacket on a whim during the David Reeves bespoke sample sale. Beautifully made garment and a great deal. But for altering the sleeve length, it fits like a dream.

But now that I have it, I am struggling to think what to pair it with. Medium to light grey flannel trousers seem like the easy answer - but do you any other suggestions?

I'm all ears.

Suggestions please - pairing a charcoal sport coat.