I found these https://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!
Long pants are the only thing that works for me as well - even in the good old days of being a size 8, I never had a thigh gap. I like the ones from the Big Tights Company, and Chaffree are also good. Both are on there third year of use, and the Chaffree are at the end of their life, but the others are still as new. I've tried every gel or cream known to woman, but nothing works like fabric!