Saddle suggestions please

[mavandkaz]

I am really struggling to find a saddle to fit my 'new' boy. When saddle first came out he put him in a Bates GP which fit well. He quickly billed out and it became too tight over the shoulder so saddler came to widen it. Since then we have had issues with it slipping back, and with lumps appearing alongside his wither. Saddler been out to try and refit, but nothing is working. So now looking for a new saddle - unfortunately saddler doesn't have anything suitable in stock (other then brand new for ££££, which I'd rather not as hes going to change shape being only 5 and newly backed.

So suggestions please for something that has a wide channel. Flat, wide panels. And ideally something that sits behind/away from the shoulder. He has a huge walk with lots of movement and swing through the back. Although he's a 'chunky' chap he has a wither, and is currently in a wide gullet.
Some pics attached although they are a few months old, and he's muscled up since. Although still lacking topline (not got any recent ones unfortunately)

 

[lme]

Stride free?

 

[Suechoccy]

My cob (3/4 cob, 1/4 TB with wide back, not much wither) is in an Ideal event saddle for my hacking.

My half cob/half TB, wide back, not much wither, is in a Harry Dabbs close contact saddle for my hacking.

 

[nutjob]

My wb who has a wide flat back, a large shoulder and quite a lot of wither was in an ideal 1350 gp when I used to do a bit of jumping.