I would also add Austin/Colin and Erin. Erin keeps in touch with all her partners (some more frequently than others iirc she mentioned this on the cribs ITT) and quite a few were invited and went to her wedding.

Interesting that no one has mentioned Matt di Angelo and Flavia or Count Dracula and Jemima from playschool (Ali) as they certainly seemed to have a warmth towards each other during the last couple of series.

I would definitely have included Matt and Flavia but the OP said not including the romances

My god she'd SQUASH him!

... friendly this year; Flavia & Jimi. seemed to get on well.

GARY!! (shudders)

Definitely agree, they got on very well. I would also add Patsy and Robin get on well Whatever he has done to help her to re-gain confidence has been working wonders. Oh and I forgot to add to my post earlier we can't forget Chris and Ola they had a brilliant friendship

Definately Erin with Julian, Colin and Austin

Yes I seen most of the last tour cast in the hotel after the show last yr in Glas and Erin had came to meet them, you could tell she and Austin were still good mates.

Think Matt C forms good friendships with most partners, Carol Alesha and Christine defo I think

Excluding those who ended up in romances, for obvious reasons, I think there've been quite a few good friendships formed. I'm only going series 5 onwards as that was when I started watching, although it's clear to me that Ramps and Karen are good friends as well.

Ola with Kenny and Chris
James with Gabby and Zoe (he got on well with Cherie too)
Flavia with Gethin (tour) and Jimi
Camilla with Tom, Gethin, and possibly Mark Foster seeing as they've done events together!
Vincent with Rachel (and Louisa from s4 too)
Matt with Alesha and Christine
Brendan with Jo
Erin with Austin