Hopefully some members who live around your area will be able to offer you some advice. Have a look under "Servicing" , there's is a list of good and bad garages in different areas. I live in nottinghamshire and a lot of us here struggle looking for a Zed expert. Have just found a place in Nottingham..will post an update to let everyone know if they are any good. Try to stay clear off Nissan dealer if u can, they charge about £80 in labour per hour ex VAT.
PM R35LEE or ZMANALEX if you need the OEM parts..far cheaper than Nissan stealers. They are top blokes