Yea, definitely don't put them outside yet (assuming you live in Britain),
but (if you have the space to do so) give them their final (big as possible) pots now,
so their roots can go deep and develop nicely as soon as possible.
This will signal the plant it has the opportunity to grow big.
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When you say 'right now', do you think they are ready? or do you mean, when I do pot them up, use nice fluffy soil?
It still seems a bit cold to put them in their final pots out on the balcony.