Think we're due a bit of news here, it's been a while. Seller seems to have gone and its been ticking up recently. Perhaps news of an acquisition is on its way.
Yes you can move a s&s isa to a new provider( as long as they recognise / offer the stocks you have) and open as many new ones with as many providers as you like. Just remember the total you can invest in the 2025/26 tax year, in any isa or across multiple isas is Β£20k regardless of the type of isa.