Next Available Number in Range

[Marhier]

Good morning, I hope you're all well today.
I'm trying to find a formula that will give me the next available sequential number in a range of cells.

Use case:
I have an order register with a list of sequential schedule numbers (Column A).
Once an order has been placed, I put the order number in the respective cell in Column O.
I might order schedule 024, before I order schedule 016, so the order numbers aren't typically listed in sequential order.

What I'm After:
In cell V5, I want to put a formula that looks that looks at range O9:O1008 (or PurchaseOrderTable[Order Ref 2] - table reference) and tells me what the next number in the sequence is.

Potential Issue:
Sometimes, an N/A gets put in one of these cells if a schedule has been cancelled, or placed on a credit card, so worried the moment a text value gets entered, it'll throw that formula out.

Any help would be greatly appreciated.
Thank you.
Regards
Marhier.

 

[Marhier]

I've been quite meticulous with the formatting of each cell, due to lots of people interrogating the data, using the autofilter fucntion, plus having a lot of buttons that do various things with the data.
All of the alignments have been done on purpose - the only data set hard right is currency.

Not meticulous enough though, so it seems!

Thanks again mate.
You've really helped.

 

[jasonb75]

Not meticulous enough though, so it seems!

I work on the theory of 'just when you think that you've made something idiot proof, they'll send in a bigger idiot to prove you wrong'.