I believe a type of rocket was used to "Blitz" London.

Yes. 'Flying bombs' as they were sometimes called. I think the Germans called them the V1s.

Any help from our older Brit chums?

Not that old, thank you very much - just interested...

For what it's worth, I believe the significant developments in peace-time rocketry in the US depended a great deal upon Germans who, post-war, headed for the States (usually invited by the government eager to get a-hold of that technology) and settled there, taking their knowledge of the V1 etc with them.

cheer

the sunshine warrior