[ColinWright]

Start by deciding on acceptable routes. Here's a graphic of a recent journey I computed:

http://www.solipsys.co.uk/images/Route_HOO_HWY.png

Choose your date and time window for travel.

Then for every leg, download possible times and prices. Finally, simple search for the optimal combination.

You don't have contact details in your profile, but if you email me I can send you more details. I'm extremely busy just now, but if we establish contact I can send you relevant things in slow time. Let me know.