While E45 is a good moisturiser its not designed to long lasting, its for live skin, you need a leather restoration cream/liquid or similar.
As with leather its important to clean it first, dried up oils and dust create a very effective abrasive and also lever open cracks. If its a buffed finish isopropyl alcohol or similar is good for cleaning old oils/waxes that have accumulated but would probably prove difficult for a suede finish. You might have to be careful if its is dyed.
Syntec produce (relatively) cheap easy to use products, a liquid rather than a cream will be far easier to use on a suede finish.
If you want the to be waterproofed then you may need to use a final waterproofing as well.