I didn't worry when I got mine. I cut it as required to fit the wallet. I thought that's what everybody did? There were no instructions to say you shouldn't cut it. Honestly if anyone ever wants to see it uncut, I can scan it into the computer and reprint it in a similarly poor quality. It's not like it's a one of a kind special issue with a hologram, water mark, magnetic strip, or chip.
Unsurprisingly many years later no one has ever even commented on the fact that I cut it to fit the wallet. I even cut the replacement pages. I may have even used a guillotine!
The CAA do keep an electronic record of the licence, so they do know if you have one, and if it's current (assuming they didn't lose the form).