So have I got this right?
My DC's are uncrytalised pots? At the point I start to draw down, or want to take 25% tax free, it becomes crystallised?
Yes.
With the proviso that you don't have to crystallise the whole of any one pot at one time. Only the part you put into drawdown and/or take the TFLS from is crystalised.
Suppose you have a £80K pot, and want to take out £20K over the next 4 years till it's all gone. In the subsequent years you have...
[End of Year 0]
£80K uncrystallised pot.
[Start of Year 1] - you crystallise £20K of the £80K uncrystallised pot. You end up with...
£60K uncrystallised pot
£5K TFLS which you take out immediately and buy that OmegaB from eBay that you've always wanted.
£15K in a crystallised pot which you draw down as income at £1250 per month, paying whatever tax you are liable for.
[End of Year 1]
£60K uncrystallised pot
One OmegaB
[Start of Year 2] - you crystallise another £20K from the remaining £60K uncrystallised pot. . You end up with...
£40K uncrystallised pot
£5K TFLS which you take out immediately and buy another OmegaB from eBay for the missus.
£15K in a crystallised pot which you draw down as income at £1250 per month, paying whatever tax you are liable for.
[End of Year 2]
£40K uncrystallised pot
Two OmegaB's
[Start of Year 3] - you crystallise another £20K from the remaining £40K uncrystallised pot. . You end up with...
£20K uncrystallised pot
£5K TFLS which you take out immediately and buy another OmegaB from eBay for your son.
£15K in a crystallised pot which you draw down as income at £1250 per month, paying whatever tax you are liable for.
[End of Year 3]
£20K uncrystallised pot
Three OmegaB's
[Start of Year 4] - you crystallise the final £20K from the uncrystallised pot
£0K uncrystallised pot
£5K TFLS which you take out immediately and buy another OmegaB from eBay for the daughter.
£15K in a crystallised pot which you draw down as income at £1250 per month, paying whatever tax you are liable for.
[End of Year 4]
0K uncrystallised pot
Four OmegaB's, and a realisation that buying OmegaB's from eBay might not have been your greatest idea.