Hi Dean.
The Mullard Guy artic would be one of London Carriers,owned by the Philips Electrical Group.They carried a lot of cathode ray tubes etc.
The D and D Iveco could possibly be D and D Transport from Dundee,it does have a Scottish plate. If so they were commonly known as Dusk till Dawn and Dawn till Dusk Transport,make whatever you like of that. 
The Hill’s Crusader isn’t the one from Botley,they were from Derbyshire - maybe Ripley. Somebody will put me right. 