Ternary plot with ggplot - add legend and remove labels

Question

This is only me second post so please forgive my ignorance! I've used ggplot to create a soil texture ternary plot with custom polygon fields and custom area because the USDA soil texture fields aren't compatible with UK soil surveying. I've created something I'm mostly please with but I cannot figure out how to add a legend to the figure and how to remove the labels from the triangle points :-

I've tried adding colour outside the aes field which I think should work but I couldn't get it to work. I also tried adding labs in scale_colour_manual which gave me a legend but for the background soil textures and the measured soil texture points. I can't help but think I'm missing something simple but I can't figure it out! Here is my code:-

UK_text <- UK_soil_texture_classificationiii  %>% group_by(Label) %>%
  summarise_if(is.numeric, mean, na.rm = TRUE)
UK_text

UK_text$Angle = 0
UK_text$Angle[which(UK_text$Label == 'Loamy Sand')] = -35
theme_set(theme_bw())

ggplot(data = UK_soil_texture_classificationiii, aes(y =Clay, x = Sand, z = Silt))+
  coord_tern(L="x", T = "y", R = "z")+
  geom_polygon(
    aes(fill = Label), alpha = 0.000001, linewidth = 0.5, color = "black")+
  geom_text(data = UK_text,
            aes(label = Label, angle = Angle),
            color = "black",
            size = 3.6)+
  geom_point(data = Ternii,
             aes(x = sanda,
                 y = claya,
                 z = silta,
                 color = area), alpha = 1)+
  xlab("Sand \n(2.00-0.063mm)") +
  ylab("Clay \n(<0.002mm)") +
  zlab("Silt\n(0.063-0.002mm)") +
  scale_color_manual(values = c("red", "blue", "green", "dark grey", "yellow", "purple"))+
  theme_showarrows()+
  theme_clockwise() +
  theme(text = element_text(family = "Jacobs Chronos")) +
  guides(fill=FALSE, color=FALSE) 

I'm still nor sure how to create a reproducible example sorry! I created an excel sheet with all the polygon points for the UK soil classification and then used geom_point to add the measured data in another spreadsheet with some minor tweaks based on another guide I found to change the angle of one of the labels so it fitted. This has all worked really well, I'm just struggling to remove the labels at the triangle points and keep the arrows and text and add a legend for just the measured soil texture points