Complex one here I think.....

I have a coumn of strings, for example:

CPSAINSBURYSAE0401001
CPAE0401001SAINSBURYS

...what I need to be able to do is extract from the strings the following:

LLNNNNNNN
(L= Letter, N = Number)
So if we applied this to the above examples, we would have a result of:

AE0401001

Little bit confusing, hope its clear enough, really need help on this one.
Many thanks.
Ash.