What do the seals look like, can you get one out as a sample.
If so I am sure you can purchase a normal seal - "O" ring or whatever.
Point of fact, I was quoted R300-00 a seal for fork seals on a Honda Cruiser.
I took a chance and took the part to a motor spares shop, they measured it and
it turned out to be the same as a wheel bearing seal on a Nissan Bakkie.
I bought the seals for the bakkie at R7-00 each, fitted them and did 10 000 kays
without a hitch.
As a matter of interest some Suzuki oil filters are the same as a Daihatsu Charade,
R15-00 from Midas
Off you go to the motor spares shop my lad