If you could not emember anything then you were right to make a no comment interview. It is for the police to prove the case, and if you cannot remember then you are entitled to see that there is enough evidence to show that you are guilty.
i take it that you were picked out at the ID parade and now accept the position and will plead guilty.
You have crossed the threshold of 120 where custody must be an option, but in reality unless there was a nasty accident or other aggravating circumstances, as SuicidalDepressive said, custody is unlikely in reality, but you will probably get a community order and a ban of 29-36 months.
you can get this reduced by up to 25% if you are offered, and accept, to attend a Drink Drive Rehabilitation Course. You should be offered it by the magistrates. If they forget, ask before you leave the courtroom, as it cannot be offered once your case finishes.
as for the insurance, it depends what your policy says. Some say you should notify them when you receive points or a ban. Others say to notify them at renewal. If you intend your partner to continue to drive on the same policy after you are banned then you could have. A problem as the premium is based on two drivers, and there will only be one which is a change in circumstances that you should be telling them about.
The problem is that some insurance companies cancel a policy when they are informed of a Drink Drive ban. That would cause you problems when you want to be insured in the future and you are asked: “have you ever had a policy cancelled....” if your company is one of those, you would be better to cancel the policy yourself, because that doesn’t count as a “policy cancelled” ..... by them.