I looked on the web and found a tour going to Leeds Castle (w/cream tea), Dover, and Canterbury. Ordinarily I would forgo tour buses and instead find my way about myself (adds to the "adventure" of travelling), but since we are limited in time, I thought that we might be better off doing this as part of an organized tour. Any thoughts or suggestions for a different travel company?

We did a Christmas Day Tour with them. It was great for us, but I understand others on the tour had complaints. It will be interesting to see what other folks have to say.

We went on the Stonehenge and the Stratford/Warwick Castle tour back in 2000 and it was great if you want to see a couple of sites without having to arrange the transportation yourself. The guide was adequate, the only downside was that you are really rushed for time. If you really like one of the stops, too bad because you're put back on the bus and off to the next one.
But as far as Golden Tours themselves they were fine.

I did the same day tour (but without the cream tea) with Golden Tours in October. I too normally forgo tours, however the day tour was nice to take advantage of limited time. My only comment is that I could have spent longer in Canterbury or I could have spent the entire day at Leeds Castle wandering the grounds and gardens (plus the weather was beautiful) but that certainly is not a criticism of the tour company. Dover was about right -- basically just a "photo op" stop but it was cold and windy on the beach so everyone was ready to move on.

It's very difficult to find any tour that allows exactly the amount of time you would like to stay at any particular stop if you don't do it all yourself. But then, I enjoyed the tour guides' commentary and learned a little bit from them that I might have missed if I'd done it all on my own.

I also took another Day Tour (to Stonehenge and Bath) during the same trip with Evan Evans tours. Both companies had similar tour lists and were very close in price. I would gladly take a tour with either of these companies again. The choice between the two would probably boil down to the same thing it did last time -- which one offers the tour I want to take on the day I want to go?

I thought the Evan Evans tour bus on the tour I took with them was a bit nicer than the one on my tour with Golden but there was nothing wrong with Golden's bus -- a sample size of one each from each of the two companies is not large enough to say that Evan Evans has nicer buses than Golden.

By the way, not sure when you are going, but you can actually book once you get to London. For each of the tours I took, I booked the day before I went -- one I arranged through the concierge at the hotel; the other by phone. Unless you are going at a very busy time of year, I wouldn't pre-book before I got to London. This will allow you to retain maximum flexibility in your schedule and adapt to weather, etc.

And I meant to add, during the busier times of the year, they add additional tours so even then, I wouldn't book too far in advance.

Thanks to all for your advice. I pre-booked for the trip with londontown.com...they offered a discount over the published price (which I verified with the Golden Tours website). We're leaving in less than 2 weeks, so that's why I already booked the trip. However, I can cancel up to 1 day in advance. We are scheduled to go on a Monday...thought that was better than a weekend as most people will be at work, so we shouldn't encounter the traffic of a weekend when people are at home.