Hi Steve
Could be Solent, Viking or Hermes as they had four bladed :think:
Most Freighter and I think the Hermes had a large cooling fan.
That could be left off there but no point in that.
Is it definately civil...could be Valetta, Varsity or Hastings.....even some Halifax had four bladed......The Noratlas was another four blade Hercules user.
The type of Hercules would narrow it right down :think:
Garry