Are you looking for new or used?
The reason I ask is that for £150 you can only get an eheim capable of filtering upto 350 litre tanks.
I know you have a 330 litre tank but I would recommend getting a larger filter. As most others would recommend the same.
I have a 200litre moderately planted tank and I use a fluval 206 (rated for upto 200litre tanks) filled with siporax, the original sponges and polishing pad. I then also use a fluval U2 (rated upto 110litre tanks) internally in my tank with everything that comes with it. My plants also act as filtration.
Due to you wanting a cichlid tank you probably aren't going to be having real plants so you need a larger filter to compensate.
Have you checked out charterhouse aquatics?
They are the cheapest online i have found for brand new equipment.
If I were you I would look at maybe something like a Fluval 406 along with an internal stick on something like a fluval u4 internal.