Chiltern seeds may be a good start .

Thanks for the reply but chiltern seeds have aconitum but no ferox spp.Any other suggestions? Cheers

I can't imagine why you would want to grow this, it's 1 of the most dangerous of all poisonous plants, but also a valuable medicine, when it's prepared by someone who knows what they're doing, just handling this plant can cause serious effects.
This plant is used in some dangerous tantric rituals, and can cause death if used incorrectly. A few grams of fresh or dried plant material, or 3-6 mg of aconitine can kill an adult, it has been used as the poison, on poison arrows.
I would strongly recommend that you steer well clear of this particular plant, Derek.

I wonderd why Chiltern seeds didn't sell them .

Aconitum ferox is not native to the UK so I don't know how easy it is to grow here.

It looks very like the A. napellus that is very common so it may be that there isn't enough demand to make it worth selling.

As above, it is poisonous, but so is the napellus and that is very rarely a problem as far as accidental ingestion is concerned.

As Thepoisonga points out both A.napellus and A.ferox are equally poisonous, A.ferox is used in Ayurvedic medicine where 15mg of dried plant material is used orally as a medicine! I think this is the real reason why ferox is not easily obtainable (have-a-go ayurvedic practitioners could result in disasterous consequences). Cases of aconite poisoning usually occur by ingestion of medicinal herbs especially in China and Japan.
I want ferox seeds because i am interested in plant rotation to try and reduce nematode infestation in my garden this has being partially successful with A.nepellus.