EJM,
I too offer a very warm welcome to this beautiful forum. Nice to see another UK citizen join the ranks.
Just a few rambling thoughts, Spearmint is quite effective as long as you drink at least two cups of tea a day. I do appreciate it is possible to purchase it in capsule form but as yet I have not found a source in the UK. The decaffeinated tea bags are more readily available via Ebay sites and the-spice-cellar I have found to be the most reasonable especially with their postage rates. Do not be tempted to go for Supermarket ' mint & spearmint' it is not the same and is very unlikely to produce sufficient (if any) Anti-androgen benefit.
I have been on NBE for almost a year and taking PM for nine months of that year. The PM is a life changing herb and not only will it, given time, bring about breast growth but it will certainly and quickly give a new feminine benefit to the mind.
Yes there are other attributes too with skin & nails to name but a few. Beware though it does weaken erections it will be necessary to lay off the PM for a week or two if intimate sex is required. I lost my erections a while ago and to be honest I don't miss them one little bit, in fact it plays nicely into my future dreams.
My growing breasts are a concern to my wife more than me, yes I do have to be very careful and now I am unwilling to remove my shirt. I did make a grave error of judgement by agreeing to take the grandchildren to the swimming baths. I did manage to hide the 38B protrusions with my towel or arms until safely submerged below the water line. All was well until I absent minded stood up to assist my grandson and caught sight of a couple staring at me until I quickly submerged my body again.

So in saying this, keep in mind some of these inconveniences.
You are very lucky indeed to have a wife who reconciles your need to go down this road, mine certainly does not and has threatened divorce if I go too far.
Take care and I wish you all the very best on your journey.
Hugs
Heather