thanks guys, it's been on the wood a few months, but the tank didn't have ferts, and it was growing from nearly dead bits that had been half eaten by my SAE's and then left for months dried out on the inside rim of the tank, so it started off slowly.
i gave it a trim, and took off the string, and it has attached itself really well. i put a little more string on, as i used some of the trimming to fill in the gaps.
cheers 😀