I think the original question remains valid and unanswered though.
I too have ISA holdings I’d like to move to Freetrade.
I will go ahead and “assume” that Crest-able stocks in my current ISA that are also within the Freetrade universe will be fine to transfer in specie,
So the questions remain
What about Crestable stocks in my ISA that are not in the current Freetrade universe? Sell and transfer as cash?
Foreign Stocks (mostly US) that are actually held in Custody with a US custodian? Would you take them in certificated form with a medallion guarantee? Would you transfer directly to your own US custodian? Would you insist I sell and transfer as cash?
I think that’s what @gmullebr was asking too