How about this.
1. I have been advised that if I take periodic payments from my SIPP I can claim 25% as tax free as it would be tax free in the UK (I am US resident now and NT tax code in UK so no UK tax). No lump sum.
2. I have been advised that because I did not exclude the contributions to the SIPP from my US income (I didn't 8833 the contributions), I have a basis in the SIPP and only pay tax on the profits on the SIPP. So let's say my contributions to the SIPP were 60K and it's now worth 100K - I pay tax on the 40K profit.
3. Now here's the kicker - on which I could use some advice and have someone check my logic. I can't see anything in the treaty which indicates how to apportion the withdrawals between income and capital, nor how to use the 25% tax free element. What's to stop me using the entire 25% tax free element for the profit (which is taxable) withdrawn from the SIPP? So in the case of the aforementioned 100K SIPP, let's say it's withdrawn in 10 equal chunks of 10K each. I know the first 6K of this is tax free as it's the basis, and 4K is taxable. But 2.5K of all this (25%) is tax free according to the 25% rule. Can I apply all that 2.5K tax free element to the 4K taxable element? Or how about taking 2 withdrawals a month - one for 6K (tax free - withdrawing some capital) and one for 4K (withdrawing profit) and apply my 25% against this 4K? Ergo I pay tax on 1.5K / month rather than 7.5K /month?
A