Images NOT centred inside the caption

Hi
The caption on my image is aligned left – but I want it centred.
here is th ecode

[caption id="attachment_914" align="alignright" width="315"]<img class=” wp-image-914 ” alt=”Sophie and Sabina from PA Business Support” src=”https://www.pabusinesssupport.co.uk/wp-content/uploads/SophandSabina.jpg&#8221; width=”315″ height=”225″ /> Lunching with my colleague Sabina[/caption]

I have tried adding this code to the style sheet:
.wp-caption img {
margin: 0 auto!important;
padding: 0!important;
border: 0 none!important;
}

I added it above
caption, th, td {

font-weight: normal;

text-align: center;

}

but no change
what should I add where?