I had only bought a set of four replacement tyres and the spare remained a cross ply, so on the occasion I punctured I swapped the flat near-side rear wheel for the spare.
I nearly sh!t myself when I went round the first roundabout with the mixed rear tyres. The rear of the car slid out dramatically, rally car-style and I drove immediately and gingerly to the nearest tyre fitters for a new radial (the old one was beyond repair).
That rally car broadside moment was reproduced on my Brompton, riding in the wet with the rear Schwalbe Marathon tyre (or at least reproduced the same brown pants net result).
The weather this week has been wet and so I was grateful I had swapped the rear tyre for the Panaracer and am pleased to report that it grips far better. I haven't experienced any wheelspin on wet drain or manhole covers and no broadsides.
Or at least, no rear wheel slides - I did experience a front tyre slide, maybe from diesel on the road, so I'll keep an eye out for another cut price Panaracer to fit on the front.