UTA is Roy Gripskie & sons own brand and believe it or not. actually made in Australia.
The 3 blade blade carrier was a good idea mechanically but a failure in the market place as blade & bolt sets come in 2 or 4 blade packs
From memory it takes a Superswift / Jetfast blade & bolt or a Greenfields Blade & bolt .
You need to be a little careful because the thickness of the round section for the blades to swing on is different because the Greenfields blade goes on the ride ons & is thicker than the Jetfast which goes on a walk behind .
If you in OZ go to the
RGS web page and use the "find a dealer " then go to the dealers web page and look for the MSSA affiliation which usually means they are a full repair workshop & not just a glass front retail outlet .
You could try phoning RGS as most of the staff are ex-mower shop staff not spotty faced computer jockeys so usually can nut out obsecure branded mowers.
I did come across this problem way back & from memory it took a couple of tries to get the right blades & not real sure if we did not end up cutting Super 24 blades down to fit because that is one I keep bulk .
If you are outside OZ then measure the thickness of the blade then get back here &I Will go down & pull a couple of blade packs apart to measure the bolts .
If you have more problems with them then come back & I will see what can be sorted out
If you do get it sorted then please follow up with what you fitted so others will know