Scorpiomikey
Almost every kit is available somewhere. Just a matter of how hard do you want to look for it and how much do you want to spend on it.
Yeah, the cost is the big thing with the Eagle. $50 and up is a bit much for me right now. Also, while the memory of building that with my dad is a treasured one, it was the planes that really got me interested in modeling ( I remember asking my dad if the Spitfire literally shot fire at the enemy or used an aerial smokescreen to confuse enemy pilots to earn the name ).
I checked out the Airfix kits you mentioned and they look like a match from what I remember ( as I said, it's been about 30 years ).
Now, next big question: does it have to be the same edition? I found a 2-fer from Airfix ( has both the Spitfire and the 109 ) that's more recent, but the parts for the 109 that I was able to see look the same as I remember. There's also the potential issue of 30-year-old decals if we're going with the original issue in my case...