Ann: Appendix 4D and Half Yearly Report and Accounts, page-17

I derived the fraction rate of approx. 0.11 from discussions with the company I had a few years ago about the amount and origin of unrecognized losses. Because I just love a good hidden asset that nobody understands
And a tax shield is the same as more margin.

Don't think what you state is correct, one can never utilize more transferred losses than the fraction * taxable profit for the year.
In your example no more than 0.11 * $50M is $5.5M. Hence lowering the taxable amount by 11%, _effectively_ droppig the tax rate from 30% to 27%.
The history of the company of which the losses were transferred is relevant in the sense that the transferred losses must be in the same category (capital losses, foreign income, film (?!), other as the income for the year.

How about I revisit the discussion with the company, and provide them with a simple example, assuming non transferred losses to be fully utilized in 2025. They seemed quite knowledgable and helpful.

Is there a direct mesage function @ hotcopper by the way?