I'm planning to take the may19-june 1 tour, but find it odd that period is bracketed by sold out tours. Anything going on in England that a traveler should avoid during that period? Or is it just lousy weather, which this Seattle resident shouldn't complain about...?
From Monday, May 20th to Saturday May 25th will be the Chelsea Flower Show in London, which makes things slightly more crowded. However, that shouldn't affect your tour much. No, shouldn't be lousy weather. Should be beautiful, perfect weather; however, always be prepared for at least one or two days of rain in England any time of the year!
" Anything going on in England that a traveller should avoid during that period?" Since the tour seems to cover a fair bit of England (though misses some of the "best of", in my opinion), I think it is safe to say "no", perhaps in one town or other but not across the whole country. There is no Jubilee or Olympics in 2013 (sadly). The weather can hardly be a factor given all three are in the same four week period. Perhaps a couple of family groups have already booked the preceding/subsequent tours and that has filled them up before the rest?
Remember these are not big group tours, max 24-26 people and they don't run multiple tours at same time, so the fact you have tour full before and after doesn't mean that much..
Pretty much peak time as soon as school is out in the States, and only 2 dozen folk per tour. You thought about that week and others did too. There's the Spring Bank Holiday on the 27th of May. - = - There is no Jubilee or Olympics in 2013 (sadly). I'll give you that, but I can offer you a Coronation Festival at Buck House in mid-July if that would help...