In reply to Chris Harris:
From the Nikwax website:
'Nikwax TX.Direct® Wash-In is the market leader. It is easy and quick to apply in a washing machine, and its highly Durable Water Repellency (DWR) develops on air drying. The washing machine application ensures that the treatment goes right through the garment, treating seams, tapes and cords, as well as the fabric. Also, as the need for tumble drying is removed, this saves energy and protects more vulnerable, older, garments from heat. Nikwax TX.Direct® Wash-In has been specifically designed and optimised for breathable waterproof garments; it leaves a flexible water repellent treatment on individual fibres allowing moisture vapour to pass through, maintaining breathability.'
Note that it mentions the need for tumble drying is removed!
Fluorocarbon-based proofing agents, such as Grangers Xtreme Repel, on the other hand do definitely need heating to activate the proofing agent.
So, since you don't have a tumble drier, stick with Nikwax TX wash in. I use it annually on my Paramo gear as recommended by the manufacturer, Just be sure that your washing machine and detergent tray are scrupulously cleaned of detergent before using TX, since any trace of detergent (other than pure soap) will reduce the efficiency of TX.
N