triple s charge about £100 plus postage for powder coating, so that's sounds great. Trust me get it done by motorcycle powder coaters, not garden gate vendors. I had a test peice done from one of the garden gate coaters and it was shite, more orange peel than oranges!!
Your would need to csand blast that frame anyway, so let the pro's do it. Just make sure you degrease everything first or the powder will take on a sheen when its heated up.
BTW, start looking for new stancions on ebay etc as they will need doing and to rechrome is another £135!!
drewps