Martin Skidmore edited and published a magazine about comics called FA for some years, over 20 years ago, stopping when he was too busy editing a line of comics called Trident. FA still has a lingering good reputation with old comic fans, so the name was used again here.
FA wasn’t the full original name: before Martin’s time it had been called Fantasy Advertiser, but he changed it to the short form for lots of reasons:
1. It didn’t sound like a sexual contacts mag.
2. It didn’t sound as if it would be mostly adverts.
3. He didn’t like the implication that comics and fantasy should be inherently linked.
4. Most people routinely referred to it as FA anyway.
5. He liked the meaning of the term in the phrase “sweet FA”.