i was also looking here when i was going to buy one https://babymattressesonline.co.uk/120-x-60-cm-ventilated-foam-safety
https://www.amazon.co.uk/gp/product/B00CBAWDXY/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 Its out of stock now. i paid £21 but they have this one that is 7cm which would do just as well https://www.amazon.co.uk/Mother-Nurture-Fibre-Mattress-120x60cm/dp/B075H1Q41J/ref=sr_1_5?s=baby&ie=UTF8&qid=1524141478&sr=1-5&keywords=120x60cm+cot+mattress
Where did you get the seperate mattress please? Can't seem to find any 120 x 60 anywhere - thank you
Back in stock.