@JackJack84 it's great that you are doing well and are stable, however, you definitively need a referral.
If you, or a Sibling has bi-polar there is a 50% chance that you may develop Puerperal Psychosis, this can usually be avoided if there is a care plan in place and you choose to take medications after birth (anti-psychotics, such as Olanzapine for example)
The trouble is, many people haven't heard of Puerperal Psychosis, or have any experience of it, including health professionals.
It effects around 1 in 1500 women, so depending on your midwife she may never have come into contact with anyone who has had it, or may be at risk of it.
I think that given you have had previous episodes of psychosis, it is absolutely essential that they refer you.
Another poster mentioned the charity Action on Postpartum Psychosis - they are wonderful and there's lots of information on their website. I think this is a case of needing to take ownership of your own mental health (which you obviously do, and have already) and educating your midwife who by the sounds of it, is a bit naive/ignorant.
Don't be scared, forewarned is forearmed and by getting a referral and a proper care plan in place it will give you the very best chance of continuing to keep stable and as well as possible.