gummed up egr valve

I own a vRS mk1, BLT. Am having a engine management light come on. Took it to a couple of garages and they said  system regulation range exceeded p3130 intermittant. Had fault cleared, drove it hard to clear out the system but EML came back on. Been told by both garages that replacing the EGR is a difficult and time consuming job which i presume could mean super expensive.

Can anyone shed any light on this? can i do it myself?

does the vacuum box it connects to also have to be replaced?

thanks