Auto numbering in corresponding row

[Aussie Grid]

I need to have the corresponding row numbers auto update in column A, if it is blank, whenever new data is added.
i.e. If there is no row number in A7 when I enter data in D7 then auto enter the row number into the corresponding row in col A, A7 in this case. Obviously do nothing if there is a number in corresponding row A8 if cell G8 is selected etc.
I also need the numbers in A to auto update when a row is added or deleted.
Possible?
Any and all assistance appreciated.
Aussie Grid

 

[Jon von der Heyden]

Thank you Jon that is almost perfect. The only draw back is when a new row is added, the formula isn't in col A so there is no number.
Any ideas?
Thanks again
Aussie Grid

Perhaps use a table. Lets say you currently occupy A1:Z10, and you have headers in row 1. Go Insert > Table. Choose range A1:Z10 and check 'My table has headers'.

Next make sure that the formula provided is entered in A2:A10.

Because this is a table, each time you enter a value into a field in a new record the formula in column A will automatically be copied to the new record.

 

[Aussie Grid]

Sorry Jon, it works Ok on deletion of a row but when a new row is inserted it wont work as the formula isn't in col A. Tried copying it all the way down to bottom of sheet, went to insert row and was told there was no room for my data etc.
Aussie Grid

 

[Jon von der Heyden]

Have you tried my suggestion in post 11?

 

[Aussie Grid]

Just tried the post 11 solution Jon. It works perfectly, thank you very much for your assistance.

Aussie Grid