Alpha numeric excel data validation

[taliapaw]

Hi when I was checking my data validation formula I found it failed terribly.
The format I'm trying to obtain is: AA##AA####A
A is alpha a-z and does not need to be case sensitive
# is numeric 0-9

the formula I was using =AND(ISTEXT(LEFT(D1,2)),ISNUMBER(MID(D1,3,2)*1),ISTEXT(MID(D1,5,2)),ISNUMBER(MID(D1,7,4)*1),ISTEXT(LEFT(D1,11,1)),LEN(D1)=11)

it failed when I tried the following [TABLE="width: 85"]
<colgroup><col width="113" style="mso-width-source:userset;mso-width-alt:4132;width:85pt"> </colgroup><tbody>[TR]
[TD="width: 113"]aa123a1234a[/TD]
[/TR]
[TR]
[TD]aa12341234a[/TD]
[/TR]
[TR]
[TD]aa12aa12345[/TD]
[/TR]
[TR]
[TD]1a12aa1234a[/TD]
[/TR]
</tbody>[/TABLE]

I also just stopped testing at that point. Any help would be greatly appreciated. Thank you in advance.