Fitting a fireplace to a flat wall, dimensions???

[loujords]

Hi, Im new on here, just hoped someone could advise me please.
We are replacing our fireplace, Ive picked the surround and fire but need some help with a cast iron insert (back piece) We have no chimney so its against a flat wall. The surround has the capabilities to house an electric fire with a 75mm recess, the fire has a 70mm recess but I would love a cast iron surround. Just been looking at the dimensions and it say 25mm depth, some say 75mm depth. Does this have to be added to the fires depth?, if so we wont have enough room . Im so confused now. Thanks for any help.

 

[PrenticeBoyofDerry]

I'm confuse too
Could you explain it again please, may be with references to the model/type of fire and the surround you want.
I guess you don't intend to make a cut out in the wall for the fire to sit?

 

[loujords]

Im even more confused now Ive re read my question lol.
Thanks for replying, I think I may have the answer now re my initial do I have to add the surround depth to the fire depth.... yes I do, but after visiting a couple of shops today, one says I can have what I want and one says I cant???? I can save nearly £500 by buying online but it would still be an expensive mistake if it wouldnt fit.
We live in a semi and are having the party wall soundproofed so the wall has got to remain flat. (One shop said chip to the brickwork to gain the extra mm's) This is the wall where the fireplace will go. There isnt a chimney so we have to have an electric fire. Ive seen the Dimplex Exbury which says it has a 70mm depth and Ive asked the fire surround seller if the surround can accomodate this fire with no cut out in the wall. He says it can as the surround has a 3 inch recess, which will allow the fire to sit flush between what ever back panel we chose and the wall. Im told this will work fine with a granite/marble back panel but I would love cast iron. If I could find a flat cast iron back panel then it would be fine I think but they all seem to be moulded which is what Im having to allow for in the dimensions. Some say 25mm depth, some more and this added to the 70mm fires depth means it wont fit flat aginst the wall. We dont want to use the spacers you can buy with the fires, I would like it to all fit flush. Im not really fussy about which back panel I have, just something that will fit. The ones I liked were the Gallery Chamberlain, Monroe or Hamilton Cast Iron Inset. They are all slightly moulded 'inwards' towards the wall to give a 3D sort of effect. If I could get one flat with any detail on the front of it then I 'think' we may be ok.
if you get this far lol, sorry its so long winded, I cant think how else to explain.