I appreciate it seems like a pain, but if the area is local to you it's worthwhile taking the trouble to build up a relationship with them. The posh phrase is probably 'Networking'.
At the moment they don't know you from any other scruffy 'erbert. Once you get to meet them, and they get to see and listen to you, the arrangements may become easier and more 'local', like a phone call to xxxx.
But you may well have to jump through the hoop a time or two before it gets to that stage.
The CAA licence question is just standard, the question has to be there, you just say officially 'N/A (Private flight)'.
For a flight plan, tell them the maximum height limit you expect to set (which may well be 120 metres), and (perhaps unusually) the maximum distance from the take-off point you will set. Don't forget to set it, on that occasion at least. It there is anything of particular interest, that you will be making a Point of Interest, put that in.
They want to know what to expect, they will be reassured by it.
Tell them (don't expect them to know) that you will keep within VLoS (although doing that in a 'forest' might be challenging, I guess it depends on whereabouts on any hill you will be taking off from).
Ask if they want to visit you flying.
Yesterday I was offered a choice, launch adjacent to some trees at 149m above sea level, or travel less than quarter of a mile and launch adjacent to some other trees at 214m above sea level. The choice was obvious, to me. This was farm land, not FC land.
Basically, do whatever is necessary to establish a positive working relationship with the people who work on the ground. It will pay dividends in the long run.
Regards.