We are re doing our front garden from grass to gravel.
im looking to get something like the picture around out tree would I need to cement down and between the bricks or do I just gravel around them?
You will certainly need some kind of solid base below the brickwork or it will settle unevenly over time. Most permanent would be a hardcore or scalpings base and the set the bricks on cement.
I have done brick circles in the garden. Laid on a base of sand. You get stuff from the builders merchants for in filling. It comes in tubs, about 45 quid a tub, like fine silica sand which sets. Just brush it in. I have also laid a circle and just brushed a weak mix of sand and cement in the cracks.
You can lay it on dry mix (sand and cement) and it will harden in place. You must ensure the underlying base is well compacted otherwise it'll just sink. If your gravel is also well compacted you shouldn't get any movement. Fill in between the cracks with dry mix too, but you might need to make sure it can run out at the sides otherwise the rain will just wash it away over time. You could use more cement in your dry mix to prevent this but be careful not to stain your nice new bricks.