Burnet Moth Caterpillars - which kind?

Burnet Moth Caterpillars - which kind?

Observation - Burnet Moth Caterpillars - which kind?. Description: I've found 2 caterpillars - both of which I think are burnet moth caterpillars. However, I think they look slightly different and was wondering if anyone knew how to ID them please? Maybe they're the same... The first two images are of Caterpillar 1 (t

I've found 2 caterpillars - both of which I think are burnet moth caterpillars. However, I think they look slightly different and was wondering if anyone knew how to ID them please? Maybe they're the same...
The first two images are of Caterpillar 1 (taken at the start of the month) and the second three images are of caterpillar 2 (taken today). Caterpillar 1 seems to have white spots on his head? Any help would be appreciated.