Transferring from a topped up ISA question

BarJK7

Hi,
I have had an existing cash ISA account (NS&I) for quite some time that already had a balance (pre this tax year) and then I added this year's full allowance as well.  
Now I have read about transfers of ISAs from various sources but unfortunately I am still confused. 
Do I have to either transfer all of this years' allowance over* (if I want to open a stocks and shares ISA), or does the fact that I had an existing balance from a previous tax year's allowance mean that I can transfer a smaller amount to open up a stocks and shares ISA and maybe also an Innovative Investment one (leaving most in my cash ISA intact)?
Alternatively, do I need to wait until April 6th when presumably I can transfer whatever proportion I want to other ISA account types?
If that* is the case then to slightly complicate matters I am thinking of switching cash ISAs as mine currently has a low 0.8% rate. 
Thanks in advance

masonic

You can transfer the full £20k you added this tax year to either a S&S ISA or IF ISA. Alternatively, you can transfer any part of the money paid in during previous tax years to a S&S ISA and/or IF ISA (while leaving this year's £20k with NS&I). As well as transferring some previous year money other ISAs, you can transfer the full £20k from this tax year to another cash ISA.

After 5th April, you can transfer any part of the £20k as it will be treated as previous year money.

I'm presuming your NS&I cash ISA is not flexible (their Direct ISA isn't).

BarJK7

Thanks Masonic, yes it's an inflexible Direct ISA. You have reassured me that I can do what I am looking to