Central locking issues

[Rich23]

I have 2012 Dispatch, only have manual keys 1x original 1 x aftermarket.

Cannot unlock drivers door, with either keys, however can unlock rear with both keys.

Can lock drivers door with keys but no relay clicking hazzards coming on etc.

Can hear relays and Hazzards flash when locking/unlocking from rear.

Kind of annoying when you want to get in and drive off.

Any idea of what it is and is it easy to solve.

I know the battery is on its way out. As when I got in yesterday was flat.

Can get in as cut out airvent at top of bulkhead to get longer materials in. With long stick and hook can pull open door handle and deadlocks release.

Thanks for your thoughts.