Sadly it's a common problem Mick - Just remember that if you get an unexpected email asking for ANY personal details IGNORE IT!!!
If you think there is even a small chance it could be genuine, phone the company concerned and ask - but make sure you look up the phone number yourself, do NOT just blindly dial a number which is listed in the email!
At the end of the day it comes down to common sense, but some of these spoof emails do look very convincing! So take Micks advice or suffer the consequences!