@ John
Its a parallel threaded fitting. On disassembly I found that the male thread was evenly coated to the end with the sealant. However only the top two female threads had sealant, although it looked like an even coating. I had only applied sealant to the male part as per instructions, and it would appear that because the threads were so good excess got scraped off after the first two threads. It may have been a different story if I had coated male and female threads.
However the real killer is that the sealant clearly dissolves with paraffin. And I'm betting it would with any other oily bits, despite the tin saying that its resistant to petrol and oil. I suppose it depends on how you define resistance, but I would say the performance is poor against these petrochemicals.
I am about to remake the joint with Swan Seal, a ptfe compound (it says on the tin).
Best Regards
picclock