That all sounds positive, hopefully you get a real Openreach engineer with a Nokia 4-port ONT. Don't sign off on the job being completed if they show up with the same one you have and it doesn't improve anything, push back so they mark the task as not completed and then maybe someone else can have a look.
Is it only the Nokia 4-port that will suffice? Are the Huawei and Nokia the only options they offer or are there others? I will certainly say no to another Huawei (and I was very clear on the phone to BT that an upgrade is needed, not a replacement) but are there other makes/models they might install that will also do the job?
Openreach have had 4 vendors for FTTP. They are ECI, Huawei, Nokia and ADTRAN.
They provide the ONT for the home and at the other end of the fibre the OLT in the exchange.
Most vendors want their ONTs to connect to their OLT's and the OLT's are configured as such.
They dropped ECI long ago and haven't installed ECI kit in exchanges for coming on a decade, if not slightly longer.
Did to political pressure they dropped Huawei from new deployments but there remains a very large proportion of Huawei kit in the exchange.
Nokia and Adtran are the 2 current vendors for new deployments.
They install Adtran ONTs for Adtran equipment (OLT's) in the exchange, and Nokia ONT's for Nokia OLT's.
Due to the large amount of Huawei kit already installed in almost every fibre exchange (aka head-end exchange) they cut a deal with Huawei where Huawei would do some kind of licensing allowing Nokia ONT's to be installed in customers homes to connect to Huawei OLT's.
AFAIK no such deal exists with Huawei and Adtran ONT's.
So new FTTP installs will be either...
Nokia ONT on existing Huawei OLT in the exchange
Nokia ONT on Nokia OLT in the exchange
Adtran ONT on Astra OLT in the exchange
If Huawei had remained an active vendor they would/could have delivered Open reach a more capable ONT but as it stands the only 4 port they provided Open reach was picked long before gigabit services were being sold.
So the only option for replacing a Huawei ONT is a Nokia ONT.