Much better progress since the soil was changed from a high nitrogen soil base to a lesser dense packed nutrient based soil. John innes number 3 - Things are finally looking promising for the growth.
It looks like you've had the same problem since the very start..! D:
Do you not have any way to balance teh soil out..?
Perhaps you can use something such as lemon, or pine needles, or a little vinegar in the water?
I'm not sure there's any way to stabilise the pH of the soil long term, without mixing in fresh peat or mulch - though, there's nothing wrong with washing away the soil from the rootball and replanting it at any time.
Some lost growth time is better than it dying..! It's so far along!
I hope it will be ok..!
//sorry, not peat, compost!