Hi, Dryden, sorry to be slow in replying.
In 5d, I certainly wondered whether either “convenient” or “old” was an extra word, but then I checked the definition of the answer in Chambers and found that the relevant definition began “formerly”, so justifying the “old”, and could be equated with “convenient farmland”. So there were no extra words – the definition is “convenient old farmland” (I think that the word order is OK for a crossword clue).
The clue that I was sure right until the end had an extra word was 19a, where I couldn’t see the need for “Scotland” in the definition. It was only when I couldn’t get the endgame out (I had one S too many) that I checked the definition of the four-letter synonym for “truly” in Chambers. I found that this meaning was given as specific to North America and Scotland, so “Scotland” was actually part of the wordplay.