Ender 3 Pro print problem

Hi,I'm fairly new to 3D printing, I've started so that I can produce some parts required for my job.I have printed about 150 parts so far all without a problem. Suddenly I've started to get issues that look like under extrusion. To try and fix this I have changed the nozzle and PTFE tube. This has improved things slightly. I've printed bed level tests and all seems ok.I've attached some photos that show a completed piece, as it should be and some of the issues I'm seeing.The filament has been used before with no problems so I've ruled that out.Can anyone give me any pointers please?Thanks,Ed