single storey rear extension refusal- help!

[amp1978]

We have been refused planning permission for a single storey rear extension (3m) for the following reasons:

1, pitched roof
2, loss of out look to one of our neighbours (not loss of light)

We have a semi detatched house and our adjoining neighbours to the right have already built a 3m single storey rear extension. Our neighbours to the left have not extended and submitted an objection to our proposal. Our house is 0.5m staggered backwards compared to our objecting neighbours. So we have been refused permission based on the fact it would be 3.5m back from our objecting neighbour's rear, rather than 3m. There is no problem with our adjoining neighbour as they too are staggered in alignment with us and so our proposed extension would be fine for them (3m).

I am not fussed about the pitched roof issue- as there was a chance this would happen- so will change to flat... but concerned about the other issue. Am not sure of the legal standpoint? Surely we can not be penalised that our 1930s house was built 0.5m back c/o to our neighbours- after all we are only asking for the usual 3m depth? Would we really have to submit a 2.5m depth proposal instead?

Also i am hoping that if we submit a flat roof- this will help with the aspect of loss of outlook?

Pls help!