I bought my replacement blade from Survival School - on their website (
http://www.survivalschool.co.uk/acatalog/Products_with_Optional_Extras.html) it's listed currently at £15 inc VAT and postage.
Another source for laplanders is 'TooledUp' - I've bought stuff from them before as well.
The laplander is currently £18.53 inc VAT (
http://www.tool-up.co.uk/shop/diy/SAN396LAP.html) They don't list a spare blade for the laplander specifically, but there is another saw very simlar (396-HP) and the replacement blade for that is £9.55 inc VAT (
http://www.tool-up.co.uk/shop/diy/SAN396HPB.html)
Having looked at the Bahco website, the Laplander is listed (under woodworking tools!) as the 396-LAP:
A general-purpose folding saw for cutting both green and dry wood, plastic, bone, etc. Specially designed for wild-life enthusiasts, hunters and campers.
XT toothing, 7 TPI. Blade specially coated for rust protection and low friction.
Two-component plastic handle for perfect grip, with leather strap. Safety lock, locks blade in both the open and closed position.
Any of the other 396-xx blades will fit each other. The differences are:
396-HP - for hard or dry wood
396-JS - for green wood
396-JT - for soft or green wood