Fittting Lower Ground entry door/landing in 2200mm of FFL

I am looking to design an entry door to a lower ground basement that has 2200mm between the external entry height to FFL of the ground floor.

This door will provide an additional form of access along the side of the terrace to directly access the kitchen in the lower ground basement.

Due to side (right of carriageway) easements with the neighbour, I have 2200mm between the finished floor levels of the lower ground to the ground floor. 2200mm is very tight considering an allowance for 2100mm for doorway and also necessary support (joists) for ground floor flooring and for BCA compliance.

The distance between door entry to closest wall is approx. 1500mm.

Questions:
- can the lower ground internal landing be lower than the external floor level (i.e. step down into terrace basement FFL)?
- To reduce the area between the lower ground ceiling and ground floor flooring (interstitial space), are there flooring options that do not require joists/supports to be in place such as using Hebel Powerfloor?
- A final option may be to raise the height of ground floor FFL
- any other ideas to potentially achieve this?

Thank you!