This is an excellent point June and it happens frequently, I expect it is in the developers handbook.
Quite a bit of the dirty work takes place after the planning committee approval and planners should be obliged to discuss all significant changes with interested parties e.g. local Civic Society and neighbours. This consultation should be allowed, if necessary, to delay any building work so developers would have to change their mindset and show everyone their real intended design upfront.
Because a developer had offended and got away with it on a previous nearby site the Council planning committee put a specific condition on his next development as a condition of their approval. A few weeks later the developer invited a planning officer to come on a site visit and agree to his request to remove this condition. We only discovered all this by accident. It took 6 months to persuade the planning officers that in doing so they had acted illegally (only the planning committee can remove conditions put on by the planning committee). By this time the building was finished and when it had to be brought back to the committee they were told by the same planning officers right at the end of the committee meeting discussion, when we could not challenge the legality of their advice, that the Council “could not take enforcement action anyway at this late stage†and so the committee approved the removal of their original condition. This bad legal advice was later shown to be wrong, as we knew it was, and this would have been an excellent example why an equal right of appeal should be available to a third party. No one would then able to get away with these last minute tricks.
PS. An almost total lack of enforcement is the second great deficit in the UK planning system (after equal rights of appeal).