plant ID help please - some kind of cress?

I have this odd weed in my raised bed, only seen it in one place.
It has lacy small leaves, tiny green flowers, and very small green seed pods growing on branches (see second picture), somewhat reminiscent of shepherd's purse. It grows flat to the ground in a circular shape, the biggest one is quite wide, maybe 2 feet across. When crushed it smelly a bit like cress and I took a tiny nibble and it tastes like peppery cress. The seeds do look like they could be brassica family. It's growing next to rocket. One friend thought it was 'hairy bittercress' but it's growing oddly flat for that to be the case. Any ideas? thank you!