Issue #52 was something of a milestone for the publication. To the extent there had been a "lead" strip in issues #1-51, it was Stingray, being given pride of place in the centerfold. With this issue, that honor was given, instead, to Thunderbirds, reflecting the growing popularity of that show on television in 1966. While Stingray didn't actually lose any panels in 1966, the two pages that the strip was allotted were now on physically separate pages.
Price was actually 7d. That's 7 pence in the pre-decimal system, or .02916667 if converted to decimal.