The first step is to take it apart whilst damaging the wood as little as possible. For this I have a Jimmy bar and a nail removing bar... both are invaluable for work like this... oh... and a hammer. A little patience is all thats required for this so just go carefully and use minimal force where possible.
In setting out the gate I laid out two horizontal bars cut to the width of the opening with two vertical slats forming the edge of the gate with a slat laid diagonally between them. The diagonal slat needs to be diagonally cut flush with the vertical edge pieces of the gate. In order for the gate not to fall out of shape once hung, this diagonal brace must form a triangle from the lowest hinge to the latch position. This is the strongest position but as you are forming a triangle the orientation shouldn't matter really... its just good form!
Another two horizontal bars were then laid over the diagonal and vertical pieces as shown and I set about screwing the frame together. I tried to ensure the wood was as undamaged by this process as possible and pre drilled all the holes I also fixed each corner with screws diagonally across from each other to allow the screws on the other side of the gate to be fixed in opposite positions whilst maintaining the strength of the fixing points.
The facing slats were spaced out evenly across the face of the frame, and drilled and screwed into place. The hinges and latch were all new from B&Q, a hole was drilled for the latch axle (no idea if this is the right word for it), the hinges hasp and staple were all then laid out and screwed into place and the gate was mounted.
After thoughts included drilling a larger hole for the axel and the realisation that pallet wood kept out side needed some form of preservative. we wanted to stay natural with the preservative and were advised that tea makes a good preservative... my son now has a weekend job of painting the gate with strong tea as often as he likes!