Bra to wear with sundress

[slummymummy24]

Help please! I am a 34G and bottom half around a 10 but I am quite old (54) however I do still want to wear sundresses (albeit with thick straps!).
I cannot find a comfortable bra that allows me to do this - they are either too high at the back or at the side.
Anyone please have any recommendations?
Thank you

Do you have a pic of the dress- front and back so we can see what type of bra would work?

thank you for reply - it's actually several dresses but I just can't get any bras to work with them. The comfy ones are too chunky it seems! Think I am going to have to run with the underwired torture-type!