Hello, I'm having trouble colouring text different colours.
The text has no spaces and I need to use the colour dropper to select the colour.
The dropper removes the highlighted 1st 5 characters of text, stopping the 1st 5 characters having a different colour to the last 7 characters.

Hi.

That sounds like there are more than one objects involved.
Either the text was converted to path and you are using the dropper on a few selected characters only or there is a filtered object/layer somewhere above with a specific blending mode and filtering area etc.

Without a visual clue it could be anything.
Can you elaborate the working method and/or share the file in question?

Do you mean that you want each character of the text to have a different color, even though it's a single text object? I don't understand what you're describing. Maybe SVG file could help us understand?

I don't think you can do what you want by directly using the dropper tool - as you note, using the dropper de-selects the characters you had highlighted. There is a workaround, but it's slightly clunky:

1. Open the Fill & Stroke dialog (Object > Fill and Stroke)
2. Use the dropper tool, or the dropper icon at the bottom of the Fill & Stroke dialog to select your target colour. The dialog should update to the selected colour.
3. Copy the RGBA value for the colour to the clipboard (from the box near the bottom right of the dialog).
4. Switch to the text tool and highlight the characters whose colour you want to change.
5. Back in the Fill & Stroke dialog, clear the RGBA field, then paste in the value you stored in the clipboard in step 3.

That said, experience has shown that it can be tricky to work with multi-coloured text like that. Just one mis-click and the whole object takes on a single colour once more. If it's practical to do so, I usually use separate text objects for each colour, grouping them together so that I can move or resize them as a single object.

Thank you, the 5 steps worked.
I think the 5 steps is easier than the 2nd suggestion, which may require lining up text objects horizontally, which is another learning curve for me. Might be easier once I know how.

Aligning text objects is just a specific case of aligning objects in general, for which Inkscape has the Align & Distribute dialog. I cover it in some detail in part 38 of my tutorial series:

viewtopic.php?f=6&t=11981

In short, you just have to select the text objects to align, then click a single button.

Alternatively you could drag out a guide line from the ruler and enable the "Snap text anchors and baselines" option in the Snap toolbar. Then just drag the text objects close to the guide line and they'll snap into place along a common baseline.