If you've got good audio for me to listen to or some YouTube vids I can watch I may book you. Just booked a duo after they sent some promo material including YouTube links.
Or as Michael says, do floor spots.

This -

"They all want you to go to their local club and perform a few songs over several weeks before they will even consider if they like you enough to book you for an unpaid solo spot 'gig'..."

is not the case here in Burnley. If we like you you'll get a paid gig.

Persevere.....