Personally I would be a little wary about a new (2021) company only offering a mobile no. as contact phone number , with no land line or company address.
https://www.sussexdefenders.co.uk/
Yes you are correct. keeping a Series 1 is totally impractical for your new needs but luckily for you I'm happy to consider a straight swap for my D2 TD5 which has all the luxuries and practicalities of keeping a GF happy and baby safe!
As they have already withdrawn the exemption I don't see as you have anything to loose and have everything to gain by simply complying with their request!