Just thought I would say, you don't need a new matress for cot I looked at the website for kids and sids and they say second hand etc are fine aslong as stalled ok, and since you still been using it this should not be an issue. Me two eldest are 3 years aprat and I hired a capsule so that dd#1 could stay in the car seat longer and then got a booster for her when she was 3 1/2 she is very tall for her age so had actually out grown the car seat at the same time.

Looking back a pram that could take a toddler seat would of been helpfull for long trips because she would get tired and want a sleep and i would end up carring the baby.