Fireplace lintel puzzled

[Bobby2]

Hi I have opened my fireplace to find it’s not as wide as I would like I’m not sure what sort of lintel that I have but I can’t find anything online to tell me what sort it is.
I would like to widen the opening from current 22inches to maybe 25inches not for fuel use just a decorative stove heater and fake logs ect.but not to sure on what way to go forward and why the current lintel is an all in one so to speak lol
Any help and advice would be greatly appreciated as not got a lot of money to hire someone which I would rather do but times are ever changing for the worst

 

[exbg]

The lintel is only their to create the correct size opening for the fire in front of the gas back boiler. If you were to remove the plaster vertically, you will come across the actual lintel, which will be wider.

 

[Bobby2]

Oh ok thanks I’ll do that now and have a look I did think that the bricks above looked like slimmer bricks, How would I go about reducing height and widening a brick wider roughly? Would I need to put a longer lintel in under the current one that I have showing now or take that out ?