Draughty kitchen is driving me insane! Help.

[Thedogisdrivingmemad]

My kitchen is so cold and there are draughts in various areas. I have got heavy curtains and thermal blinds. I've put a draught excluder on the bottom of the back door.
I can't get replacement windows for now and even if I did they won't get fitted this winter as it's too late.

The worst cold area is near the kitchen units. I can't feel any cold air coming in through the extractor fan but the inside of the cupboards which are against the external wall (solid brick not cavity) are like a fridge.
I can't see what is behind them.
Any ideas what that might be being caused by?
There is a plinth fan heater which sits under these units and does let some cold air in when it is not on (it rarely is) but even if I cover this temporarily (obviously only when it is switched off!) that does not stop the draughts.

I'm freezing and going mad trying to work out the various sources.

Are there professional draught proofing experts? Or do I just need a good handyman type?

Cupboards against outer walls are usually cold inside.
I wonder if this is your floor? What sort of floor do you have? Concrete? Suspended? And what sort of floor covering?
Older concrete floors are very cold, as back in the day there was no requirement for insulation to be layered in to them. Our kitchen floor is a thinnish layer of concrete on earth, and it's cold. We get a cold draught coming up off it. We plan to replace what is a thin layer (6mm) of ply with lino on top with ply then a solid wood block floor, which will help a bit. If we were having lino, I think we'd put an insulating underlay down under it, on top of the ply.
Suspended floors can be insulated underneath, either from underneath, or by taking the floor up and doing it from on top.

I’m putting old fashioned curtains on my lower cupboard doors (attached to outside wall) for same reason.

I like the cupboards being cold inside and airflow in the house but don’t like the direct icy draft (esp at the sink doing dishes!)

But they’ll fit with the already eclectic ‘decor’ 🤣

Builder suggestion is expanding foam but I like the house to ‘breathe’ so I’ll see after this winter if the curtains are enough first.

That and washable rugs on the lino in ‘standing’ areas.

We got some draught excluding tape that you use in doors and put it round the inside of our kitchen cupboards to stop the draught. Worked a treat.

Well I checked again and there IS some air coming in through the extractor, and I also think various other places. I'm going to replace some of the insulating tape on the gappy windows and then get a handyman to come and sort out some other places. It really is driving me quite insane as it's so bloody cold!
@BloodyFeetByMoonlight I bet that will look lovely with the curtains but wouldn't work in my kitchen. Should do a good job on the draughts too!