Moving money in ISA

CashMoney

Hi I have an easy access ISA with Santander which matures in May with 60k in it currently at 1.50%. With the rates so low these days I am thinking of moving some of the money and then opening a Commsave credit union account and putting in say around 5k-10k as Commsave have been paying atleast 2% dividends for the past 5 years. I just have a few questions I'm unsure about.
(1) Will there be any repercussions in terms of interest earned at the end of the term of the ISA if I take some money out of it and invest with Commsave?
(2) Can I still move the 50k-55k that will be left in the ISA to another ISA if I find a better rate or if Santander reduces the rate?
(3) Will I still have the same ISA allowance (20k) in 2020-2021 and following years after removing the 5k-10k? 
(4) Is there a optimal/correct time to move money from ISA to Commsave account?

Commsave have been giving out the following dividends:
2017 - 2.5%
2018 - 2%
2019 - 2%
2020 - 2.25%

Thanks

eskbanker

It seems to me that these questions have largely been answered in all your previous threads about this, but to recap again, 2 & 3 are 'yes', and for 1 & 4, you'll earn pro rata interest on your existing ISA based on daily balances, so move from 1.5% (or the subsequent lower figure) as soon as you have access to a better rate.