Hello ,Jjgilbert...I have had mine or over 30 years,and I don't think it's anything to worry about. Mine flowered profusely for the first time,when it was much older than yours,and apparently, it does so when stressed ? This is the only thing I have been able to find,as to why.

I've found mine doesn't flower every year ,and only has one flower, this year..
It is natural for it to drop quite a few of yellowing leaves at this time of year, I'm finding lots too.

I have watered mine sparingly this last week,first time since before Christmas. Maybe that's why some old leaves are dropping ? but that's just my thinking..
Anyway,yours looks really healthy,as does mine, and is also in a Conservatory. East Facing,and unheated....

I have repotted mine only a few times,in all these years,in fact it's had some drastic pruning of the roots,and sides,to no ill effect ,so I could keep it in the same pot !
I hope this helps..

Hello Bloomer - thank you very much for your reply. I’m hoping that the yellowing and leaf drop will lessen. It’s beginning to look a bit bare in places…! I thought that maybe the energy used in very abundant flowering - more are appearing - has been detrimental to the leaves. I keep my fingers crossed that the flowers aren’t it’s swan song. The conservatory temps are very low in the winter also, but it’s now way too big to move elsewhere. Thank you again.

You're welcome,Jj..I'm sure it will survive, with or without flowers,as they seem almost indestructible.. After the severe treatment mine has had at times, after all these years,and is still looking good, says something Lol. If you want to take cuttings,just in case the worst should happen,,they are so easy to do,and I've done lots from mine over the years,mostly to grow on for Charity events,and friends..:o)

Thank you Bloomer - I have 6 quite large cuttings already, but after so long, I would be so sad to lose this one. It started off being a very straggly sick plant belonging to my daughter. It came here for TLC and recovery and never went back….! I hope when the weather warms up it might feel better….