I expect the flower drop was due to the move. Many plants do this when suddenly shifted from one site to another. As there are more buds coming don't worry, it will settle down in its new place. Someone else I'm sure can give you some help with its culture.

It likes to dry out a cm or two between waterings, and a good drenching when you do. it will also lie a 3-1-2 proportioned feeding at 1/2 of the rate recommended on the package, Bright indirect light, within 3 feet of open sky, or sunlight filtered through a sheer curtain will help it to continue blooming. Don't let it get chilled by the window in the winter.

Thank you both. I would feel awful if I killed it off.

The RHS site has some very useful information about maintaining Stephanotis. I really thought mine would die, all the flower buds dropped and several of the leaves but after standing it on gravel so that there's no water retained by the soil is has perked up.
https://www.rhs.org.uk/Plants/17784/i-Stephanotis-floribunda-i/Details

Thank you Hazeyboo. Does your plant stand in a decorative pot and you put the gravel in the bottom of that?