Can anyone give me some advice on the following:

Myself and my sister were offered a dilapidated property to purchase from our parents a few years a go but didn't have the funds at the time so it has sat empty waiting for us to begin.
I have now sold my investment property to finance the renovation and have commenced the work but my sibling does not have any money to contribute.
I feel that she should have some of the property as it was initially offered to us both and she could have said no to me doing it.

Can anyone suggest a fair way of dividing this for both of us?

You need to have a working agreement, really. If your sibling is unable or unwilling to put money into the property, I doubt you could force them to, or try and claim extra value on a sale on account of the extra investment you made.

I don't think you can blame her on this - this all looks like a case of bad planning and preparation, in which case, time to fix that.