Hi Andy,
Did you first notice this issue after update to WordPress 5.7? The button alignment bug that you are reporting appears to be due to a styling issue for legacy button blocks that was introduced in Gutenberg 9.3 and included in WordPress core 5.7. There is a bugfix in place to correct this issue for Gutenberg 10.5, however I’m not sure when this version of Gutenberg will be released.
I would keep an eye out for upcoming WordPress core updates, but in the meantime you can 1. replace the buttons with new button blocks — only legacy button blocks are affected; if you use the updated buttons block, then center alignment should work correctly, or 2. apply inline styles to center your Gutenberg button blocks. For example, to center the buttons on your Tours page (https://edinburghcabtours.com/tours/) with inline styes, open the the Gutenberg editor for the Tours page, and:
1. Ensure that align center is selected for the button block
2. On the button block, Select the More Options (three vertical dots)
3. Select Edit as HTML
You will then see something like this:
<div class="wp-block-button aligncenter is-style-circular"><a class="wp-block-button__link has-quaternary-color has-text-color has-background" href="https://edinburghcabtours.com/tours/city-centre-tour-2-hours/" style="background-color:#1b2dd0">read more</a></div>
You will want to add style="text-align:center;" to any button div that you would like centered. The Tour page buttons block html should look like this:
<div class="wp-block-button aligncenter is-style-circular" style="text-align: center;"><a class="wp-block-button__link has-quaternary-color has-text-color has-background" href="https://edinburghcabtours.com/tours/city-centre-tour-2-hours/" style="background-color:#1b2dd0">read more</a></div>
Once Gutenberg 10.5 is release you can remove this inline style fix. Let me know how that works out for you!
