I messaged this and as usual got no response.
After several days with no response I messaged again only to get a message back from DI saying they are very busy and will think about it.
Historically this is very familiar.
In the past I have invited them to come away with us but there is always an excuse not to come.
It's not just holidays but I've invited them for days out or meals even before they had their daughter.
Is it that you cant see it - or won't accept it?
You need to read between the lines here and adapt before you do permanent damage to your relationships.
Some might see you as pestering and that they are holding right back and not wanting to be rude directly.
I would accept and adapt that they currently dont want to spend these times with you. Thats 100% their perogative. Stop begging and pestering. Step right back and try a new approach. Cherish the opportunity you have with your DGD. They value enough to entrust her in to your care - so take that as a win.
Give them some space and distance and start afresh in a year or so. This will show that you are respecting their boundaries. Start small - something focused on DGD - maybe a short activity locally - maybe your DS might just go.
Accept and adapt is the way to refresh and redirect relationships that are unsettling.