3 month old hates Phil and Teds in newborn mode - what to do?

[purplelover]

Every time my 3 month old is in the P+T she seems to be really unsettled and cries most of the time.
She seems as if she is getting too long for it too.
This is beginning to restrict what I feel comfortable doing with both children on my own as I can't hold the baby and push the toddler etc at the same time.
We started off with a cocoon but sent this back as the straps seemed to fold in into baby's face. I then lined the base with a blanket and most recently tried the moses basket mattress.
Anyone else found this and what age of youngest did you move to double seat mode?

I had to move DC2 to sit in the main seat with it reclined a bit, and put DC1 in the extra seat; I know they aren't supposed to until 6m but I started when he was 10wks and just tried to avoid him bieng there for long. I figured it was like sitting in a bouncy chair. He was just too big to slide in underneath!

I moved my ds2 when he was 4 months old I think. He was huge though and we lined the doubles seat with a lambskin liner which reduced the depth a bit. Could you use a car seat on top and have dc1 in the second seat - I think you can do that with the newer p&t now can't you?