some of my leaves turned a yellowe colour
Phil, you may be overwatering. Just go to misting only for a couple of weeks, no dumping water into the bowl.
Serrisas, as I said, can be finicky. It may also just be going through an acclimation (getting used to) period in your home. Phil, if the
tree is getting indirect light, don't move it around alot. Keep it in one place.
For more specific advice, join the bonsai help forum I linked you to. Here it is again.
Bonsai Help They are
true bonsai experts. And the forum comes from the UK. You may find some bonsai lovers right in your neighborhood!
Beginner bonsais I recommend are juniper and fukien tea. They are more hearty and a bit easier to care for.