I think you will find that it’s the Council’s planning committee who are calling it in! It means they will not let the designated planner decide it on local policy. The committee wants a more detailed look at it.
However, you have to understand that it must meet planning requirements. They cannot make it up as they go along. Being overlooked from a distance rarely means a design will be turned down, new or extension, and you can plant a few trees but remember a hedge should not be over 2m.
Regarding an appeal. It seems the Council think they will lose. They can be asked for costs if they vexatiously turn down a reasonable application. Of course it costs money to defend their decision and if it’s in line with their policy, they cannot defend turning it down and the Inspector will give permission anyway. If the Planning Officer recommends approval, it’s poor use of scarce resources trying to defend the indefensible. It really matters not one jot who knows who. Planners know all the decent local architects. Architectural merit doesn’t trump all planning policies but must be assessed regarding quality of design. You could ask that they include a privacy glass balcony around the terrace for example. Or Venetian style fencing. 2 m high.
20m is over 60 ft. Many roads are not as wide as this. You can plant trees as others have suggested and you must be totally aware of the planning policies so you can mount a challenge. Obviously contact your local Councillor for the Borough Council who decides the application. However, if you have been told it meets guidelines, it does.
Regarding building new homes in general, yes people can build larger houses. Some people have Range Rovers. Does this make them awful people? They probably pay lots of tax so support the NHS more then lower income families. We all aspire to earn quite a lot and enjoy our large homes that we have worked for. Why do people always pick on the better off?