Thanks for all your responses. So I have seen two luthiers. Options include:
1. Bringing the bridge back 2-3cm toward the fingerboard. I tried this, and reset the sound post to match but I don't really like it. Cello sounds better with the bridge aligned with f hole notches, however the bridge angle is incorrect (sloped backwards). Its a compromise.
2. A neck graft to correct length and angle. The back length on my cello is fine just the neck length and angle are not perfect.
3. One luthier suggested resetting the neck, however my usual luthier respectfully suggested that this would change the fourth position because the top nut on the cello body's back has to be aligned with the neck, so you can't make the neck 2-3cm shorter easily this way.
4. The cheapest option is a surreptitious piece of ebony at the nut/saddle to shorten the string length. This does not correct the neck angle.

I have already had a fingerboard graft however it corrected the way the neck sloped to one side. To correct the whole neck angle would have made the graft and the neck very thick.
I am using light strings.

The other cello in the photo is a loaner made by my usual luthiers. Its AUD35K. It looks much smaller as its a Guadagnini copy. My cello is insured for $15K which I interpret to mean $10K if I wanted to sell it. My luthier's formal advice is to get another cello as correcting this neck issue is not guaranteed to make it easier to sound, and will not improve or decrease the resale value. However, it I am desperate to change it he will do a neck graft.

By difficult to play I mean that the spaces between the fingers, especially in 1st to 3rd positions (assuming correct intonation!) are larger than normal, especially with finger extension, and this adds a level of fatiguability. Also if I play with the cello in a natural position for me, I am bringing my left arm and shoulder back more than say on a cello with a normal neck angle. I tried alexander technique and holding the cello baroque style with the neck forward. This is sort of OK but I do like the endpin.

Thanks again for your comments.