It was all going tickety boo until I upgraded the TCMS3 3.5.0-rc.10 I now get this:-
Sun Jul 05 11:48:33 2026 ERROR PHP Fatal PHP Fatal error: Uncaught Error: Class "Composer\\Autoload\\ComposerStaticInit4331eb47263b7b493714fa7e109e5051" not found in /home/sites/34b/7/747b57d6b7/sandbox_html/site-assets/stacks/tcms3/tcms/vendor/composer/autoload_real.php:32\nStack trace:\n#0 /home/sites/34b/7/747b57d6b7/sandbox_html/site-assets/stacks/tcms3/tcms/vendor/autoload.php(22): ComposerAutoloaderInit4331eb47263b7b493714fa7e109e5051::getLoader()\n#1 /home/sites/34b/7/747b57d6b7/sandbox_html/site-assets/stacks/tcms3/tcms/autoload.php(3): require_once('/home/sites/34b...')\n#2 /home/sites/34b/7/747b57d6b7/sandbox_html/index.php(14): require_once('/home/sites/34b...')\n#3 /home/sites/34b/7/747b57d6b7/sandbox_html/index.php(47): smart_require('/site-assets/st...')\n#4 {main}\n thrown in /home/sites/34b/7/747b57d6b7/sandbox_html/site-assets/stacks/tcms3/tcms/vendor/composer/autoload_real.php on line 32