thanks guys! yes she has Da Bird, in fact i had to get up from my afternoon nap today as she was pestering me to play with her. She got knackered after half an hour and has been asleep ever since haha!
that said, she does charge about the flat quite a bit, usually for about 15 mins at a time a couple of times a day so i'd say for an indoor cat she's fairly active but obviously nothing compared to one that can go outside.
her little "spay sway" looks like a proper little belly but as soon as she's rolling about it becomes quite obvious it's mostly skin so maybe we're overreacting but it's better to be safe than sorry!! she's quite petite otherwise, she's about 3 years old and can't weigh more than 3.5 kg!