I have found too that sometimes a lamp, which is tested ok, wont work in a fitting, even with a new starter. However, if I fit a High Frequency starter, all is well. I cant say that I have tried turning them around, will try that next time.
We are going to start sending the duff ones back, all those £1.50 add up!
It does seem that thee old fittings last the longest. We have some from the late 60's working well but the new ones last about 5 years. It also seems that the starter type fittings last longer than the HF fittings.
