Hiya! Welcome to the forums and to Slimming World! Sounds like you've had a fantastic loss so far, huge congrats to you!
All fat free natural yogurts (including Greek style) are free on SW. When I get sick of Muller Lights I tend to switch to these as they go really well will fruit, aren't really sweet and you can add various things to them to make them taste better (I don't really like them on their own). Sometimes I like to use a fat free natural Greek style yogurt, mix in a little bit of mixed spice or cinnamon and it goes really nicely with chopped apples and satsumas. If you want to use some syns, a few raisins are really nice with it (3.5 syns for 25g) or you could use your HEB on some other dried fruit or nuts to mix in for a bit of a change or a nice crunch.