Plum Interest rate

Fatherjacob

Hi im wondering if anyone has had experience with Plum and transfering an exsisting Isa ?
Ive just had my exsisting ISA from Santander to Plum made today £20000 , apparently with plum the rate from exsisting isas that are transfered in goes down to 4.29 % from the 5.17%
Im just trying to figure out if i was to then add new money to the account would the transfered in money be at one rate and any new money go to the higher 5.17% rate? 
Alternatively will the rate just stick at the 4.29% for all the money.
Not the quickest company to have a response from ,so i figured id ask here first.
Never know your luck ! 
thanks for reading ,any help is greatfully received.

slinger2

I had a look at this account. However the basic interest rate is variable, as is the bonus. You only get bonus at all if you stay for a whole year. Also it's not a flexi ISA. So if they cut the interest rates after 9 months I can either wait another 3 months to transfer out or transfer out immediately but lose the 9 months of bonus. Non-starter for me.