So the defence case is that you should have been taken to hospital, where a blood sample would have been taken which would show you were over the limit, instead of being taken to the police station where a breath test showed you were over the legal limit.
It has been pointed out by several people that you not getting medical attention is a police complaint matter, but it has NO impact on the fact that you have been shown to be over the limit.
Please treat what happened as two separate matters. The court will pay no attention to you not getting treatment, because it had no effect on you blowing into the breath test machine and being shown to be over the limit.
You have already committed to hundreds, probably thousands of pounds of solicitors fees and you admit you agree you are going to be banned, so what have you gained from your expenditure? Please do not spend more money on what seems to be a futile quest.
What you should do (and you can do this yourself without a solicitor) is to write to the police and ask for a copy of your custody record and the video relating to your detention and being breath tested. You can then review this and if is shows you detailing your injuries and the police officers ignoring what you said then you have grounds to make a formal complaint.
What happens with police complaints, unless the allegation is of a serious assault, is that they log the complaint but only investigate properly AFTER your court case is concluded. This is to prevent people making complaints in the hope that their case will be dropped... the complaint is separate to the case against you.