It wasn't the 7th FCC report but the 9th (2000) when semi-auto sub 12FPE air rifles were considered.
9.19 The Home Office view that low-powered self-loading rifled air
guns are not subject to Section 5(1)(b) of the Firearms Act 1968 should
be confirmed at the first legislative opportunity. [Paragraph 11.26
Steyr LP50 pistols have been on sale for some time. What's the difference in law ?
Sub 6FPE semi-auto pistols legal, sub 12FPE semi-auto rifles legal. If classed as not specially dangerous your O.K. to own.