I thought it was SHOUTING!
Anyway, back to the original question: no, there is no keyword search on either season number or episode number. Only one field has range searches, as far as I can see.
You can search on episode name, which is sometimes a string composed from the season number and episode number, but that isn't the case for Antiques Roadshow. But anyway, even it it had the episode number in the episode name, you'd have to enumerate all the episode numbers you want to record.
Searching on desc won't help, that's the description of the episode and rarely (if ever) has the episode number. E.g. for the episode "Lowther Castle 2" of Antiques Roadshow, the description is:
The Antiques Roadshow makes a return visit to Lowther Castle in Cumbria where they discover an army of Action Man figures, a giant skeleton clock and rarely seen watercolours by Beatrix Potter.
The line below it:
Series, 2015, United Kingdom, English, Lifestyle, Season 37 Episode 20
is not part of the description.
One possible workaround is to match on Year as a proxy for Season. It allows a range query, for example:
after:2010 before:2015.
You might like to make a pleasant request for searches on Season and Episode to be added. After all, the metadata is there. It doesn't seem to be an entirely unreasonable thing to ask for
