Intermittent issues arising from volatile functions

Hi All

I am having troubles with a workbook that takes a long time to recalculate. The workbook contains 4 instances of OFFSET functions, half a dozen instances of INDIRECT, and approximately 270 cells with conditional formatting on them, so I am aware that it is volatile. My question arises from the fact that, the recalculation problems (that mean extended delays for every action taken rendering the workbook unusable) only occur intermittently. When I attempt to work on the problem, the issue seems to resolve itself (including no longer asking for a re-save on closing a saved document) only to reappear some hours later.

Can anyone assist me in this? I am using Excel 2007.

Many thanks for assistance.

OD

upload your wb here

Hi Tim
Thanks so much for your offer of help. In a final look before sending the workbook off to you, I found a hidden sheet that I had inherited with the workbook. This sheet seemed to be creating all the trouble and has now been deleted.
Thanks again for your interest.
Regards
OD