depending on the size of your garden, have you considered extending the kitchen towards the garden and do the side extension? I think the difference in cost isn't much but you get alot more space. Also depending on size of your existing kitchen, it is most likely that you would need a planning permission. We got our extension done in May this year- it was meant to finish two weeks before the due date but our son arrived three weeks early! it is very hard not having a kitchen for a while and you may need to consider alternative accommodation etc but def. worth doing it. our builder was amazing and you are more than welcome to come and have a look at our kitchen if you wish.