I was watching "The Secret Garden" film yesterday and it made me remember a TV fantasy drama I watched when I was young.
I would have watched this mid 80's but the program could have been a repeat. I can barely remember what it was about but it definitely had a group of children and teenagers. One very prominent feature was that it was based in the 19th Century, based from the clothing. I remember asking my mum why the boys had long hair (one was brown and wavy). The children may have all been related family I think possibly cousins. The program was also set in the grounds of a manor mainly and they played near / in a building (or could be pavilion).
Now I am not ruling out this was some adaptation of the secret garden but it wasn't the one I watched I think I would recognize the child actors if a picture of them is found (and I think that is the best way to identify). Of course I may be mixing up details here. One other point is I most likely watched it on CBBC I remember a lot of dramas been on at the time.