PVA wood glue
Contact adhesive [sold in tins] it's what glue sniffers use so keep your nose away from it or you'll fix the panel crooked.
Seriously I favour contact adhesive but be careful when you touch the two surfaces together they must be lined up correctly you don't get a second chance.
Whereas with PVA you do.
The following is a Tip from violin case maker and has never had one brough back.
If you have any edging strips to replace smear thin layer of the Contact adhesive on the edge fix the edging strip [iron on or self glued stuff] and wipe edges with white spirit to remove any that comes out of the sides so it looks neat and tidy.
B
November 2010
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix caravans/motorhomes.