Nicky, it all depends on what the brown spots look like. If they are 'splodgy', seem wet, have a mouldy looking bit on the underneath of the splotch, then it could be blight. However, if the spots seem more of a 'spot' than a 'splotch', they seem dry, the spot is a chocolatey colour with no mould underneath, then it could be 'Chocolate Spot', which you don't need to do anything about.
It could also be scorch, if the sun came out when there was water on the leaves, or a few other things which don't mean the loss of your plants. How long have they been in for? We ate our Mimi a couple of weeks ago
