Help! no DPC under french/patio doors

Hi - I'm losing sleep over this but there is no damp proof course under both my uPVC patio doors. The uPVC door cill is 1.5 brick up from ground level below the dpc around rest of the house (which is 2 bricks up). I can see the DPC has been cut where the wall stops and pvc door frame starts.
Is the damp proof supposed to run the entire length under the pvc door?
If so, what do I need to do? Is it a big problem?

Also inside the building they put celotex in the cavity between brick and grey blocks, then cement over. The dpc above the grey blocks have been cut out as well. Is that ok? The ground is screeded as can see in photo

THANKS very much for some much needed help!!

The PVC doors are nil capillaric which means it will not absorb water and transfer it internally as a brick would. Just ensure that the cavity inside the doors hasn't been filled with cement/concrete or similar. If there is a need to fill the cavity ensure a vertical PVC membrane prevents the cement from bridging the cavity.
No need to worry in 99% of cases.

Oh no -the cavity was filled with celotex then concrete poured in. There is no vertical DPC between the cavity and the inner blocks - is that a problem?

I've seen liquid damp proof membrane at Wickes. Could I paint that on the concrete (over the cavity) and the concrete (over the inner block)?

The celotex is fine, it's there to prevent damp transfer and to insulate.
If you can remove the concrete, I'm assuming it's bridging the cavity on top of the celotex. Otherwise you might be better drylining the wall with a membrane, battens and plasterboard. A bit drastic but apart from losing 2" of floor space it will work.
Good luck
Bob

Thanks Bob. If the concrete bridging the cavity is removed, what needs to be done before laying underlay and wood flooring? Or is underlay and then wood flooring laid directly above cavity?
Thanks very much

Im assuming you're meaning the internal threshold by the door cill.
The underlay and flooring can go right up against the door cill but will probably need something to support it in case someone steps on it and I assume the doors are fitted level with the internal face of the outside brick course.
Just make sure that nothing which absorbs water bridges the cavity. If in doubt, use a piece of damp course under the underlay and up the back of the timber against the door cill.