I have an old SIP (I think mine is slightly smaller - will have to check).
The supplied fence was really dreadful, and at one point I snapped off the locking lever, too. But although I mended it, I got rather fed up with fighting it every time I wanted to set it precisely.
I bought
an aftermarket fence from Axminster, which has been a fiddle to fit, but works rather well. I note it's now about 80 quid more than when I bought (that is a HUGE price jump, Axminster!), but you might find it cheaper elsewhere (Chinese origin).
It is very versatile though, as the clamp basically has a pair of parallel sides with a locking bolt and Bristol lever through it. You can clamp anything to those surfaces, so you can in theory use smaller fences, etc. That said, the revised saw looks a bit weird as the fence is disproportionately huge, BUT it works very well indeed. My first experiment was cutting softwood "veneers" from gash 3x2 construction-grade offcuts. With a new Tuffsaws's blade I easily got a consistent 1.3mm (ish) "veneer" from a 9" length. I could probably have done better but hadn't finished the machine setup, nor was I using an ideal blade for the task.
Three words of caution:
1. You need to drill (and ideally to tap) the edge of the cast-iron table. I ignored some of the supplied fixings and went for M8 domed Allen bolts, which are strong enough and seem to work very well. The trouble is, however, that on my machine the table edges aren't finished very square to the table top (vertically, I mean), so some filing is necessary to get things to sit properly. This isn't difficult, but a bit daunting if you haven't done this sort of thing before.
I have yet to finish fitting the second rail, as the slope on that side is more awkward. That said, it works fine with just the main rail fitted (you don't usually put much sideways pressure on the fence in use).
2. The main rail ends up well below the plane of the table top. This would be fine, except that it fouls the lower door of the machine, so you either tilt the table or remove the rail for cleaning the machine after use. It's awkward but not impossible. The fence is sch an improvement I can live with the nuisance value.
3. The original rail clamped on underneath the table, to both sides of the blade-change slot, (four bolts altogether). This made the table rigid, and without the bracing effect the slot sides don't stay parallel (the table flexes). In use things get caught up on the sides of the slot - it's a right PITA.
To stop this happening, I've added my own brace underneath the table from 3/4" square-section steel tube, running the full width of the "front" of the table and using the original mounting holes from the old fence. Thus blade changing becomes rather "busy" - remove fence, remove brace, remove blade, Fit new blade, fit brace, fit fence... <sigh>.
I can see why professionals tend to have two bandsaws with different setups, as this dance takes at best 10-15 minutes with everything ready-to-go.
Hope that's helpful.
E.
PS:
this aftermarket fence doesn't look half as good, as it has many significant differences - for example the fence extrusion fits over the sliding saddle, and doesn't clamp to the side of it - not as versatile.