Hi all.
I bought an SL at the time, but because of me hurrying I thought that my standard freewheel was 18T. I was wrong, its 16T. My freewheel is placed on the rearwheel and the SL would give me a shitty low gear ratio. I could then replace the front chainring/crankset to a bigger one but instead I returned the SL and bought a ViZ Seventy Two (recommended by tarty).
I couldn't find much info about the ViZ but this freewheel seems to do the job for me. I have ridden the bike a couple of times since I replaced it and Its definitely much better than the standard one I had before.
Thanks again for all the answers