sjj:

But have I lost the right to put my £5100 subscription anywhere else?

No, you have a seperate allowance every tax year. Previous years fundings and transfers are entirely seperate.

You can still subscribe £3600 (£5100 if over 50 by next April) into a 2009/10 ISA with any provider of your choice.

I had a 1 year fixed rate cash ISA which matured in June 2009, as it already contained £50k plus I knew the ISA limits were increasing in October, I simply transferred the whole amount into a new 1 year fixed rate ISA with the same provider but did not add any more to it. Now October is here and I have suddenly thought have I been stupid? I know I cannot add anything to the existing ISA as it is a fixed term which does not allow any deposits once opened, and as mentioned before it already has £50k so I do not want to. But have I lost the right to put my £5100 subscription anywhere else?