The Times critic gave the performance a very positive review yesterday:

http://entertainment.timesonline.co.uk/tol/arts_and_entertainment/stage/opera/article4192745.ece

Although themes from the opera appear in three of the symphony's movements, they're treated differently: there's virtually no straight lifting. Several themes from Act 1 scene 1 are shared with the first movement of the symphony, and a similar relationship occurs between scene 2 and the Romanza (including the opening chords and cor anglais theme - later to be sung by Pilgrim to the words "He hath given me rest by his sorrow and life by his death" in a slightly altered version), though the last movement's passacaglia theme is also related to music elsewhere in the same scene, accompanying the Interpreter's "A room is prepared for thee". Even before that, almost at the work's outset, there's a quotation from the Tallis Fantasia, and it won't be the last time that this work impinges on the opera, either. Sometimes it's only a tiny snippet of an idea that's shared, at other times there's a recognisable contour and colour, without there being direct correlation. It would take several long posts to cover all the passages which are related.

Don't forget that before he completed the "Morality", RVW had had previous attempts at works based on Bunyan's piece, including a one-act opera and the incidental music for a radio play, and that these, too are interlinked musically with both the opera and the symphony.

[Edit: there are some striking pre-echoes of the Sinfonia Antartica at the start of Act 2: it's some while since I've heard the work; indeed my CD replacement for the Boult LPs (£8.99 in an HMV sale some years back) was still shrink-wrapped until about an hour ago. The concert programme for the public performance which was given as part of the preparations for that recording was in my hands only a couple of weeks ago, when I had to chuck it, since it had become water-damaged.]

I very much doubt you're the only one here with that dilemma, Don.