Thanks for the reply. It's a clean install and the Smarty settings are as specified in the help info. WiFi was switched off. Tried different speed testers. Switched off and on between Sim switches.
Dual SIM phone. Was sitting having a coffee. Switched between Sims. Switched phone off and on. Took Sims out and switched them over. No difference. Three was excellent, Smarty not so much.