I found these www.amazon.co.uk/gp/aw/d/B012SYTIHG/ref=pd_aw_sim_193_2?ie=UTF8&refRID=YKMZSPFJEMPWCWMBTPTA&dpPl=1&dpID=61D9fcokn7L and bought them to go on holiday- more in hope than expectation.
However, they have worked well and are lots cheaper than the Sloggi version. I wore them under skirts to walk around towns in 25 degrees with no rubbing. (I am a 14/16 so the tops can rub a little) Also they did feel quite smooth and not sweaty! I didn't get a vpl under tube skirts or fitted dresses.
Downsides- they are legging cut, so no gusset if this is a deal breaker for you. Also the waistband might be seen if you are wearing a clingy waistline. I didn't find this an issue, but could be worth mentioning.
I got ones without lace on the legs, but I can't find those me. I think I may get a set with lacy legs the make them look a little more knicker like.
Just thought I'd mention them as I know threads tend to pop up about this as the weather warms up. It might help someone who feels a bit faint at the £13 needed for a pair of sloggis!