Just a small point, but when you write to the airline (if you're doing it the old-fashioned way) send it registered post so you have proof that they received it (just in case).
Equally, if you e-mail them make sure they e-mail a response (nag them until they do), print it all out (your letter and their response) and carry it with your passport.
That will ensure they cannot deny knowledge, and any further expenses you incur should be their liability.
You know, apart from my nephew I didn't know how common peanut allergies seem to be!
I will take your advcie on board (ha ha) and definately ask for confirmation that the airline has received my letter/email - thats so helpful.
I know the supermarkets cover their backs and label everything with "may contain nuts" but drives me potty.
Thanks also for the helpful links
stars as always