XeO3: Bloody bugs!!!

I've been writing the cache code, and its simple enough, but theres a bug in it, and I can't for the life of me find it!! So I thought I'd post it here to see if anyones got any ideas. I suspect I've just been looking at it too much; not that that helps me of course! Anyway, its a simple linked list but the indexes are all +1 so that 0 specifies the end of the list. To offset this I simply subtract 1 from the address to the links which allows the normal use again. Anyway, heres to code....

        ;
        ; Y = rotation index
        ; Temp+16 = pointer to the raw sprite info with an 
        ;           8 byte cache index table
        ;
        lda  (Temp+16),y       ; get cache index using the current rotation index
        tay                    ; into the sprite cache index list
        ldx  Cache_Next-1,y    ; If we are last, then do nothing!!!
        beq  Skip_MoveToEnd
        lda  Cache_Prev-1,y    ; get the PREV from our current cache block
        sta  Cache_Prev-1,x    ; and store in the NEXT's Prev
  
        ; We've now unlinked from the NEXT item, unlink from PREV item
    
        tax                    ; and set the PREV of our new one to the OLD last.
        beq  !We_are_First
        lda  Cache_Next-1,y
        sta  Cache_Next-1,x
        bne  !SkipFirst
 
!We_are_First:
        ldx  Cache_Next-1,y
        stx  FirstCache
        lda  #$00
        sta  Cache_Prev-1,x
  
!SkipFirst:
        ; Now link the cache block to the end
        lda  #0
        sta  Cache_Next-1,y     ; get the PREV from our current cache block
        lax  LastCache
        sta  Cache_Prev,y       ; Set the LAST entry as our prev.
        tya
        sta  Cache_Next-1,x     ; and set the last entry's NEXT as our new item
        sta  LastCache          ; now set thr NEW last as the new item.
Skip_MoveToEnd:  

So.... There you go! If you spot anything, let me know - while I've still got hair!