That's the common thing with hobby MIGs, the small wire feeders don't have the reserve to push past 'use problems', so frequent tinkering like this is needed.
"Any thoughts?"
Yes. For a workshop-based project like yours, you could upgrade to a used Portamig / TecArc. £150 would be the 'cost to change' and then these hiatuses vanish.
"Any thoughts?"
Yes. For a workshop-based project like yours, you could upgrade to a used Portamig / TecArc. £150 would be the 'cost to change' and then these hiatuses vanish.