If you choose Redhill, you can follow the railway line from Dover all the way to Redhill. The longest, straightest bit of railway in the UK, which makes navigation as easy as it gets.
Heard that this was the railway line used by the Germans during the war to find London. I can second this - very straight and very easy to follow. Never been into Redhill, or Damyns Hall for that matter but remember that it has been a very wet winter in the UK, so the surface may be a little soggy. You can ring the relevant aerodromes and ask what it is like there before filing your flight plan / filling in your GAR form.
Don't mention Shoreham! I may have mentioned it once, but I think I got away with it.....
Haha got away with it thus far! Also - why would one land in Brighton (well is it even still Brighton? Isn't around 6 or 7 train stations from Brighton?) if the end destination was London (which is at least 50mins from Brighton by train + taxi + expensive + rude +...) anyway - I personally don't think that its even an option!