Can't match custom head in function signature [closed]

Question

I have written a financial charting function which has the following signature;

Chart[
    data_List,
    indicators_List: {},
    glyphs_List: {},
    chartTitle_String: "untitled"
    ]

This function works fine when I call it. I now want to make the signature more restrictive, specifically, I want glyphs to now match on a list of none or more of the custom head _Glyph. In other words;

Chart[
    data_List,
    indicators_List: {},
    glyphs: {_Glyph...}: {},
    chartTitle_String: "untitled"
    ]

To confirm the pattern matches, I have the sample argument

glyphs10m = {Glyph["RelativeHigh", 5, 5, 36.72]}

In[152]:= MatchQ[glyphs10m, {_Glyph ...}]

Out[152]= True

I can call the function with the first signature and it produces the correct output. If I use the second signature with the same arguments however, the expression returns as if it has failed to find a match, e.g.

In[168]:= Clear@"PA`"
<< PA`
Chart[data10mV, highs10, glyphs10m, "variable arguments"]

Out[170]= Chart[{{{2008, 1, 2, 14., 31., 0.}, {36.67, 36.69, 36.61, 
    36.65, 20800.}}, {{2008, 1, 2, 14., 32., 0.}, {36.68, 36.71, 
    36.68, 36.68, 2600.}}, {{2008, 1, 2, 14., 33., 0.}, {36.71, 36.71,
     36.67, 36.67, 1700.}}, {{2008, 1, 2, 14., 34., 0.}, {36.68, 
    36.72, 36.68, 36.69, 700.}}, {{2008, 1, 2, 14., 35., 0.}, {36.7, 
    36.72, 36.66, 36.66, 2800.}}, {{2008, 1, 2, 14., 36., 0.}, {36.68,
     36.68, 36.64, 36.66, 6200.}}, {{2008, 1, 2, 14., 37., 
    0.}, {36.68, 36.68, 36.66, 36.67, 2900.}}, {{2008, 1, 2, 14., 38.,
     0.}, {36.66, 36.67, 36.63, 36.67, 1400.}}, {{2008, 1, 2, 14., 
    39., 0.}, {36.67, 36.68, 36.65, 36.68, 2500.}}, {{2008, 1, 2, 14.,
     40., 0.}, {36.67, 36.68, 36.63, 36.68, 13000.}}}, {36.69, 36.71, 
  36.71, 36.72, 36.72, 36.68, 36.68, 36.67, 36.68, 
  36.68}, {Glyph["RelativeHigh", 5, 5, 36.72]}, "variable arguments"]

I feel I'm missing something basic and would be very happy if someone could point it out to me.

Thanks.