Can anyone recommend a heavy/sturdy one? DS is 12.5 months and not yet walking although pulling up and cruising (he is a bum shuffler). We live abroad and have marble flooring so the walker we have goes along really fast. He's also really heavy (almost 12 kilo) so if he tries to push it just runs away and he hasn't got a hope of learning to push it steadily! DD had the vtech one which was great but we were in the UK with carpets then. Does anyone have a really good, more resistant one?