Hmm, $150 seems like a bit of a no man's land for quality boots. Might want to consider saving up for a bit as the jump in quality is significant at the $250-$350 range. Or keep a keen eye out for sales. As I'm sure you know you UK guys are spoiled for choice when it comes to great online menswear shops, so get on some mailing lists for sale alerts. Check out Reddit and Styleforum as well, tons of good info.
The best boots I can think of near your price range are The LL Bean Katahdin Iron Works boots at $220.
The best boots I can think of near your price range are The LL Bean Katahdin Iron Works boots at $220.