[Beetroot queen]

The poly toms we inherited this year have done well BUT and its a big one, they are lovely green nice and firm but as soon as they start to go slightly red they go mushy and split. I have had to use two lots for green tom chutney all because once they start to ripen they are lost

What needs doing to sort them 

[Trillium]

It could be the variety. Some like green zebra, really are green when they're ripe and when they go pinkish, they're overripe.

[mumofstig]

Found this

Top Veg:
too little potassium leads to ripening problems, soft or mushy fruit texture, low acidity and puffiness

Have you been feeding them at all?

[Beetroot queen]

Found this

Top Veg:
too little potassium leads to ripening problems, soft or mushy fruit texture, low acidity and puffiness

Have you been feeding them at all?

we have yes but I dont know if they were fed before we got them if you see what I mean  Maybe its just time for more green tomato chutney