If you mean eurocarparts, I think you are thinking of carparts4less, nothing to do with GSF. I agree the 60% brings it down to what they should be, similar to buycarparts but they are in germany so no click n collect, slow delivery and you have to pay postage for smaller orders.
Checked on oil prices. £65 , prices way inflated to make up for fake discount. They are part of euricaroarts and they do the sane. It's not entirely useless but on the whole not a genuine discount
that's why you use the 60% off voucher! :)
Over inflated prices
I checked the cost of a battery, and it seemed very, very expensive before discount. Applying the discount brought it down to a sensible level.