Reference lookup formula

Hello all - hoping you may be able to help me again here although I think this may be a bit of a tricky one..

Basically each week I get a report on e-mail and what I have to do is add all new data to an existing report but avoid duplicates etc. What I need is a formula that looks through the existing report and picks out from the new report anything thats missing then starts a new row and inserts all the relevant fields (if any of that makes sense) The only field that is individual to each record is the ARN number.

I have attached a mock example of what I mean to help to explain this.

Tab "Main data" is the existing report and I would need to formula to start in A6 and copy accross and down

Tab "New Data" is where I will paste the data I get from the weekly report.

So any field that shows in the "new data tab" and is not already in the "Main data" tab needs to be automatically picked out and automatically added as a new row to "Main data".

While the formula is dorment - I am hoping it will not show N/A but maybe a 0 or blank cell

If this makes any sense at all I would appreciate any help

Thanks Very Much !!

HELP.zip

Thanks very much for looking at this for me - its much appreciated!

This is kind of what I was after although I need (if possible) the formula to look through the New Data tab when new data has been pasted into it and pick out only the new rows from the data (there may only be one new row in with a load of duplicates) and add them to the bottom of the main data list.

If for instance 12 rows of duplicate get pasted into the new data tab then for nothing extra to show in the main data tab

I know this is confusing and not sure if that makes any sense but if you could spare me some more time on this one it would be a huge help

Thanks again

Thanks Very Much again for you're time - I will have another look

I'm struggling to get this one working - Even if I use the one you have done in the attached sheet.

If for example I add one row to the "new data" tab then copy all the rows and paste them at the bottom

I would expect to see only the new row appear at the bottom of the data in the "main data" tab

Thanks for you're help on this one but I think this might have to be put to sleep

AK