Spotted...

What I run isn't really important (I'm on 48/19) but it sounds to me like you just need to spin more, not gear up. I don't know what 'bother' you are having on the Col du Pentonville, but I can hit 34/35mph on 48/19 so you should be able to go north of that. It's a 30mph zone anyway ;)

And yes it has been said a million times but not without good reason: pushing around a silly high gear does involve a high probability of breaking your knees. You may be ok, you may not. It's risky.

Oh, I have no bother on "le Col" (I actually named that Strava segment, if that's what you're referring to). I took pleasure in dropping an ostentatiously-clad stick insect roadie up there last night. And yeah, he was trying. ;)

I'm not a great spinner to be honest, and that's the thing. I don't mind it (and I'm a lot better than I used to be) I'm just naturally more of a masher I think. The slightly higher gearing felt like free speed.

Always room for improvement though, of course.