In message 00cc01c08be4$bd3a68e0$5f18883e@s5e8f3, Pat Sumner wildean@freedomcity.fsnet.co.uk writes
From: "Penberriss Wendy S." penberriss@yahoo.com Subject: Re: [B7L] Deliverance
The author used a rocket because it looked like a giant phallus. You're are confusing fiction with real live again. The ship didn't have to be a rocket at all.
I get the impression that the author just specified a spaceship launching.
The BBC presumably used stock footage of a rocket launch (Saturn V?) because they already had the footage, and they needn't bother creating the special effects themselves.
In fact, it's amazing how many launching spaceships in the Dr Who universe look just like NASA Saturns, right down to the letters NASA on the side. Regardless of originating planet.