About to install new architrave and skirting and i am using plinth blocks on the doors.
Question is do i install the blocks flush with the door frame or use a small reveal?

Arc is 69mm in width, with the blocks 80mm. The arc will obviously sit centre of the plinth block giving 5.5mm reveal if the block is made flush, more they are to have a reveal.

Thanks

I've put in plinths in my house. I did it to overcome awful joints at the tops without replacing all the architraves. I left a small reveal on the block of about 5mm and a slightly larger one to the architrave, about 10mm to the edge of the frame , my blocks are larger than yours so the arch's don't sit in the middle. It's personal choice I suppose , I've just never been a fan of fitting things like this flush and without a reveal.

I'd also go for a reveal. Looks better IMHO