rotor filter

Just done a service on my disco 2 td5 and the rotor filter keeps leaking oil, I thought the rubber seal had failed so I took it back to the dealer and changed it for another one, just got up this morning to find another pool of oil on the driveway. When I first took the cover off the housing the threads on the bolts came off, I managed to find longer bolts that seem to work ok and they seem to get a good grip, I've read all the threads on here about rotor filters but no one seems to have a the same problem i'm having, am I doing something wrong? a simple job that I thought I would be able to do is turning into a ball ache, Help please.

No worries, it's quite common, happened to me and to others too, i've seen few posts about that... some used helicoil, others taped bigger thread, others long bolts through the housing and nut on them...only two examples but the web is full https://www.landyzone.co.uk/land-rover/defender-td5-centrifugal-oil-filter-housing-bolts.303399/ , http://forum.landrovernet.com/showthread.php/252353-discovery-td5-centrifugal-oil-filter-housing