UPDATE:
Finally got round to calling down Palterton Lane and had a walk down the old track.
Found an old 1850's? Byron brick in an old manhole type thing in the hedge bottom
When I got home I thought about the old white sink I'd took out of the out buildings on our yard.
That used to be sat an bricks. So I dug one out from behind the greenhouse. It's Byron too, probably 1950's?
The older brick is darker in colour and slightly smaller than the newer one. Our house will be built with the newer bricks
Will drop these off for you next week Poppy. If you still want them