Thank you all, I honestly do appreciate your help & guidance on this. I agree with you @savethatkitty that it is always sided with the mother, no matter the glaring obvious facts.
It amazes me how she is able to call us names, lie by means of omission or deception & it is just how it is, however if something happens in our life that she deems unsuitable etc then it all goes crazy & our contact is threatened & her lawyer is notified.
I've started to go through all our past texts/emails etc & collate it in an online diary. Obviously I will continue to do this & use screenshots as evidence for future events. I'm also going to utilise our ring doorbell when handover behaviour is less than savoury.
Her behaviour is very erratic with constant threats or changes but then the next day ... it's all back to normal. It's very hard to get a grasp of what is actually happening.
Our DsD comes to ours and you can see the panic when you ask a simple question such as "what have you been up to", we then get a rehearsed dialogue & stumbling through it. I now don't ask, not because I'm not interested, but because I don't want to put her through it all. Everything is a secret & "don't tell daddy" etc.
Im now more realistic in what to expect & realise we may just have to go away on holiday without DSD, rather than be continually strung along until it suits to agree or not. We will need to explain to DSD why we are going away without her in a way that doesn't make things worse but it is just so sad that it ends up like this.
I feel documenting is somewhat futile as if it ever does go to court - no judge is going to read all of the nonsense. But hopefully it will at least demonstrate that we do care, we want to be a part of DsDs life and we continue to go through all the nonsense to get some contact.
We have had incidents of phones/smart watches being given to DSD & then the ex contacts & phones throughout our time with her. We now insist all devices are now put in a drawer & not allowed until home