The filter is on top of the hydraulic oil tank see picture. As you unbolt the cap you will notice its under tension as the cap is putting a spring under load. Pressing down on the cap helps to finish taking the bolts out.
Remove the cap and you will see the cr30/3 filter. Pull it out and be ready to catch the oil spill.
I cleaned my filter with carb cleaner and compressed air. My thinking is carb cleaner is made to work with rubber seals in a carb so it should be OK if a small amount gets into the system. I recommend you to replace the filter, I did this just to keep me going.
You can see the difference made, I could see bits of seal from my leaking cylinder/ram trapped in the filter.
Replace the filter and cap o ring, which comes with a new filter. Again press down cap to tension the spring and tigten down the bolts finger tight, then slowly go round tensioning the bolts so you equally compress the o ring.
Done. It's my first time doing it but it's very straightforward.