Hi George @gblair and Louis @lgardner!
Such a pity that Airfix do not replace missing parts.
The last decade, when Airfix were "cousins" with Heller and Revell sported the "blue boxes", you could ask "anything" missing from a kit and they would send it to you, ASAP, free of charge. This included deformed or broken clear parts, decal sheets, practically everything. Even if the nature of the cause could be the builder, they just send everything you asked from them, free of charge, no questions asked, provided they had it as spare, which was usually the case.
They might even take the part from one of the other editions of the kit. always free of charge, no questions asked.
I loved that approach, it was so modeler friendly and relieving and it was a plus to my brand preferences.
Seems that things have changed...
Since kit costs are not exactly low, I believe there's room for a manufacturer to easily take care of that. It is very relieving for a modeler to know that the integrity of his kit will be reassured by the manufacturer, no matter what.
Modeling community is comprised by noble people and a movement form the kit manufacturers towards the direction of free "after sales" providing missing/deformed parts will be utmostly appreciated, win-win for everybody.
I know that a number of companies, like Special Hobby, take care of that and it is a BIG plus for me!