Drop-down lists - circular reference

Hi all,

I wonder if anyone can help me...

I have a spreadsheet (attached) which I am working on to keep account of purchasing expenditure.

I have two columns - 'account code' and 'account description'. I am looking to achieve the following:

Users should be able to type in the account code if they know it, or find the relevant account description (via drop down) instead. So far, I have used VLOOOKUP so that if you type in the code, it will update the description field... HOWEVER... I cannot get it to work the other way round without causing a circular reference.

For example, I want to be able to select the 'Cleaning Materials' account, and excel will automatically populate the relevant account code (113001).

Any assistance would be greatly appreciated!

Cheers,
Martin