Fuel filter - she is changed
Observations for those that follow
When it won't come out keep wriggling and twisting and suddenly it will pop out.
Some fuel pipe connection pliers make it easier to disconnect the fuel connector. The cheap and nasty ones on Ebay that come in a set of 3 do the job - you need the red ones
The KL145 (and the UFI equivalent) is about 5mm bigger in diameter than what you are changing. This means that you cannot reuse the old tie wrap unless it was installed leaving a long tail
When it won't go in, keep wriggling and twisting and suddenly it will pop in - see above
Thanks for the help everyone