Rocker cover gasket replacement for 2.0 petrol

[Max Inc]

I've been told there is a leak from the rocker corver and the gasket should be replaced. I've been quoted £85 + parts for this job and I was wondering is this something I can do on my own?

Do you know any guides / tighneting sequence / torque settings or should I just let the professionals handle it?

Thanks in advance.