I had this brainwave the I might be able to use Chord Symbols to input Musica Ficta.
If one tries to input a sharp, flat or natural symbol without first inputting a capital letter results in a no-result.
Is there a way of making an invisible letter before the accidental symbol?
In the long run I just want ficta but until that is part of the programme one has to find a workaround that is reasonably efficient otherwise it just takes too much time.
Why not just make a playing technique that suits your needs? Much easier, and not at all a workaround. Or use staff text.
I have created the playing techniques. This definitely is the way forward.
Notwithstanding, I have set an Y offset and this doesn’t seem to have an effect on the position of the symbol directly above the staff. I would like to increase the distance from the staff…
I haven’t tried, but could you select them all in Engrave Mode (Select More) and set the Y offset there?
Another solution would be staff text. Set it to Academico or Bravura Text, and simply copy/paste the glyphs in. Once one is there, you can set the Y offset… and when you copy-paste that staff text, it will retain the same positioning. So they’ll all line up vertically.
To speed things up further, if you do it via text, don’t forget about alt+click to copy elsewhere in the score.
Last option: lyric input. Set your font to Bravura Text, and set position to “above the staff.”
I’ve used a macro program to assign the flat sign to Ctrl-Alt-Shift-F, the sharp to -S, and the natural to -N.
Honestly, that’s probably the best option, since ficta acts much like lyrics: attaching to notes as you move through the score, and always vertically aligned. If you also had lyrics in the score, you could use the lyric translation paragraph style for the ficta line.
I had to look up the term ‘ficta’
If someone could post an image here, so we can see what it is all about 
Here a video trying to shed some light into the darkness:
It’s a standard term - an oversimplified definition is just “accidentals that everybody knew you were supposed to play, so nobody bothered to write them in the score”. Except that different people had different ideas about what “everybody knew” or what everybody should have known. (Actually we have exactly the same situation today, with heated debates about the difference between C11 and Csus4 chords, etc…)
Of course the problem is that 21st century ears have a different concept of “harmony that sounds nice” from what people thought 400 or 500 years ago. The good news for instrumentalists is that often there are versions of the same piece written in lute tablature, which is unambiguous about the notes to be played.
I have another idea, which I admit I haven’t tested properly. If you use a lyrics text (a type you’re not otherwise using - translation text, say) and set the font to Figurato B, you should be able to add ficta/recta above the stave. You will find the way into getting the font and use instructions in the topic ‘Bring on that sweet figured bass’ in this forum (Sorry, I haven’t worked out how to create the link to it.) I’ve just used Figurato for below-the-stave figured bass, and it works very well.
Your ficta won’t play back, of course.
In Finale, you can select the accidental, move it above the note and resize it. That is the easiest way—and it plays back correctly. Although it will be nice to have that in Dorico someday, I can’t see making it a priority.
You can easily hide accidentals in Dorico, so that the playback doesn’t correspond to the visual staff notation. (In fact, IMO, it’s a bit too easy to do that when you don’t intend to!). You would have to add the ficta accidental separately - but in practice, there often isn’t a one-to-one correspondence between the original ficta and modern-style accidentals anyway.
Here’s another idea.
Adapt the Turn symbol in the Edit Music Symbols dialog, deleting the symbol altogether. When you want a ficta accidental above a note, add a (now invisible) turn to the note and before doing anything else add the accidental you want above the (invisible) turn using the properties panel. If the ficta isn’t in the right place then you can move it up, down, or sideways in Engrave mode in the usual way.
I like the fact that you’re not just adding a text object, which is what I’ve done up to now. Adding a ficta accidental this way seems to me to be, at least superficially, semantically similar to adding an accidental above a turn.
You can copy the ficta with alt+click, or with copy and paste.
Are there any downsides? Adding an invisible object may not be the most brilliant idea, but it’s not invisible if you add the accidental straight away. The benefits seem worth it.
Assuming your music doesn’t have both ficta and turns, of course!
Accidentals above and below work for most ornaments. There is probably always one that you don’t need, unless you want to use both French-style and German-style symbols in the same score for some reason!
First rule of notation software development: whatever limitations you introduce, there’s a piece of music somewhere that needs to break them.
Not quite right: “there’s a composer who thinks he/she needs to break that limitation, even when he/she doesn’t” 