I'm guessing it was probably me you saw, as there's not many of us left in Louth! I mostly ride here, occasionally Skeg or Clee, but I never really have the time to justify driving there.
I like riding at what used to be the Browns MG/Rover garage (next to Londis) before they knocked it down, that's a good place for beginners.
Then there is also:
The Cattle Market (really good for beginners) The Bus Station What used to be Quicksave carpark The Hospital has some good stuff too, if you enter it and head right immediatley, it will take you to some walls and gaps. The walls and steps around Kai's Bar (Wetherspoons now) The back of the building to the right of the police station (I think its social services, I've never paid attention) If you want to practise on some pallets, we used to go to Eastern Box on the industrial estate, just make sure you put the pallets back when you're finished!
I can't think of anywhere else right now. Mostly just ride what you find! Its how we discovered most of those spots.
If you ever see me out (purple brakeless 24") feel free to come say hello.