I think I'll get away with the tarmac being a bit patchy, probably will, if I've not mixed enough, make some sections to fill in later as though the road has been repaired, being set in '47-'49 then I'll explain it as repairs to bomb damage
with regards to shaping plasticard, (you may already know) that making formers and heating with hairdryer to soften or rubber bands holding it to the formers and in a pan of boiling water to soften it.