so the heating matrix has given up the ghost in my mk5 2001 car my mechanic tried everything else a year ago with the heater valves etc and came to the conclusion its the heating matrix, how easy or hard is it to replace these? i found a good one on ebay for https://www.ebay.co.uk/itm/BRAND-NEW...53.m1438.l2649

any advise and thoughts are welcome