Land possession and ownership

I’ll try and keep this short. I have lived in my house for 12 years. When we bought our house we were aware that a patch of land at the bottom of the garden was not included in our deeds but had been tended as a garden for at least 45 years and possibly as far back as the first world war. A hedge and fence bounds the entire area.

Neighbours adjacent to me have also tended a similar piece of land at the bottom of their gardens for much longer than me. The local council claim to own the land immediately beyond our gardens and are now looking to re draw the boundary.

My neighbours have had letters, such as the one we all received today, at least twice in the past and after a couple of letters back and forth the council gave up.

We are all in agreement that none of us own the land but we have all tended to it for many years as have people before us. The council have never maintained it or the land beyond.

Before we make a collective reply back to the council I wonder if anyone has any concrete advice - I like to start off with a strong factual argument perhaps quoting legislation - so that the council are in two minds whether to bother continuing their battle.

As a side note, the last time they tried to do this, before my time here, they wanted to sell the patch of waste land plus our little patches of garden to a developer to build houses. The head of council planning visited my neighbour, who refused point blank to give up his ‘occupation’ of the land and the chapped left in a complete rage. We all think the council are testing the water but want to reply with a belts and braces approach. TIA