This problem was not happening and has started since I changed back from ABS to PLA.
3mm PLA.
First layer is fine then second layer is spotty.
Same thing on top layer.
Grateful for any advice
It is probably because you are printing at to low of a temp, try raising it up. For pla most people print at 200 but my extruder was having the same problem so I raised it to 220 and it prints like a dream.