Cyclescheme and a new bike?

I feel a certain amount of disloyalty saying this, but I'm thinking of buying a new bike. The problem is that my current one needs:
- new wheels & tyres
- a new chain and set
- a new seat
- possibly new brakes and gears

The time comes when you think - well, that will probably cost about the same as a new bike. But inevitably I'm looking at spending a bit more than just the cost of repairing my current one.

My requirements are:
- needs to be tough as some weeks I do 100 miles over London's pot-holes and along the fairly rough canals
- needs to be light and fast
- needs to be strong as I'll be carrying a child on the back sometimes and normally I have paniers
- I don't want to do too much maintenance as I'm a lazy fool
- I think I may be prepared to spend about £600 - with the Cyclescheme through work you can get the bike for about half that price

Doing a bit of research and consulting my ever-obliging and highly knowledgeable bro-in-law, I was thinking of a Chris Boardman hybrid. I got quite excited. But imagine my horror when I discovered that the sole supplier of Chris Boardman bikes seems to be Halfords. And wait for it - the Cyclescheme does not have Halford's as one of the preferred partners.

So I'm back to square one and the deadline is in about 5 days. Any ideas?