Cracked Fireplace Insert

As you can see in the pictures below we have a slight crack in the insert of our fireplace. It is around 1 year old and when it was first installed, we started with timber fires then moved to turf fires as we were advised to smart small to allow the fireplace to adjust. To this day we haven't burned coal (Were told that gets the hottest).

Despite that a small crack developed in what I would guess is the "insert". It has never grown or anything like that.

The questions I have are:

1.) Is this a normal superficial crack which always develops or should it be filled in?

2.) If it isn't normal, does it pose any threat..ie should we be using the fireplace before it is sorted?

3.) To fix it, do I just get high temperature cement and fill the crack? Do you have any additional suggestions?

Thanks!!

PS. Sorry about how big the pictures are for those of you on dialup but wanted to make sure the crack was clearly visible

I'm not an expert on this but you can buy fire cement
materails and they also do a heat shield backing plate etc,
your best bet is to contact your local fireplaces specialist
for their advice. I have seen many fireplaces like yours
and don't seems to have any problem, best to give
them a ring though.

I suppose I could print out the pictures and bring it to one. Anyone else enquired before or deal with fireplaces.

your pictures show the fireback, this is made of a fire resistant clay and WILL crack with use and age.
Your installer was quite right in his recommendation to start small, this is to allow the surrounding plaster, cement to dry at a 'normal' rate without the asociated expansion problems caused by heat. After about a month you can use the fire with most fuels including coal.