Hi again Mark,
if you don't have (or want to have) the "tab-number" in cell A1 on each tab, you could replace the two A1's in the formula above with this formula:

1*MID(CELL("filename",A999),SEARCH("]tab",CELL("filename",A999))+4,50)

(the A999 could be any cell in your sheet, it is not important what cell it refers to, but it has to be there)

If your tab has other names than tab1, tab2 etc you have you adjust the formula above.

(I hope I made the translation from Swedish formula names into English formulas names correctly :-)

Kind regards
Bjorn