There are 2 pages on Goypeadia one is Balsam and the other BL's - so lots of impatiens and the members who grow them to inspire you Meanie? Impatiens is a genus of about a 1,000 species of flowering plants! You may well find in the Balsam what you are looking for?

Beware of growing Himalayan Balsam (Impatiens glandulifera) Meanie. It's a problem in some areas here as it's so invasive
http://en.wikipedia.org/wiki/Himalayan_Balsam

Have a look at this guys website he specialises in selling Rare/unusual plants/seeds etc even though he is in san Francisco I have had stuff from him through eBay and so far so good the Impatiens flanaganae that he sells sometimes look great and the size of the tuber as well
http://www.strangewonderfulthings.com/List.htm#I although at the moment he has no Impatiens for sale they will be plenty of ideas for you all his other stuff are also worth looking at

Thanks for the answers!
Steve - that is bizarre. After you question about the Deppea I must have spent the best part of an hour on his site! Some glorious stuff there including the blue Puya that is the site "avatar"!

The blue puya and tree sunflower (Rojasianthe superba) are my next seeds to conquer after the deppea and also Giant spotted Calla Lily which I have done all from strange and wonderful things

So that is Himalayan Balsam in the photo then!?
Not a huge issue to me, as seed pods only develop where I let them on all my plants. Rest assured, I will not give any away though!

Only our single native species (see my photo's) Impatiens noli-tangere. It self seeds freely around parents garden that I introduced it too :)

I would love to get hold of the giant perennial I. tinctoria with huge hollow bamboo-like stems. Saw it growing at Wisley many years ago. All you need to do is mulch the crown in winter.

http://www.growsonyou.com/photo/slideshow/114938-touch-me-not/member/fractal

http://www.growsonyou.com/photo/slideshow/114936-touch-me-not/member/fractal

Steve - the Iochroma australis, Agapetes 'Ludgvan Cross', Lapageria rosea and Turquoise Hyacinth caught my eye (and that's a very abridged list)!

Fractal - I had no idea that I. tinctoria would be hardy! Off to check your photos out now.

Meanie, your photo could be Himalayan Balsam, but I'm not sure. How large is / was the plant? Himalayan balsam grows tall. The ones I've seen were a darker pink than yours seems to be as well. More info on it here -
http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=480

Beattie; I'll take a punt that this is not Himalayan Balsam based on one thing - it was in the walled garden at Oxfords botanic gardens! Surely they wouldn't introduce a weed....
At most it was a metre high, planted in full sun. I'm frustrated because I take photos of the name tags and have deleted it for some reason..

Meanie, the Impatiens in your photo look like Impatiens balfouri, sometimes known as the West Himalayas Poor Man's Orchid which is a gorgeous perennial herb.

Meanie - Steve, just looked at this site. WOW.

It does rather!
Perennial for you maybe! Not so sure about this cold, wet isle!!

Hiya Littlelegs!
Which site - I'm throwing links around like there's no tomorrow at the moment!
Maybe strangewonderfulthings?!

Hi had Impatiens omeiana for 3 years, just coming through this year so must be hardy it has been down to -15 here this winter.