What fertiliser for grass plugs?

Hi all,

I'm after some of your sage advice. Or, grass advice to be more accurate.

I'm in Spain and I put in a small amount of grass plugs in the early summer - later than I would have liked, but hey ho. I got them from Lawns in Spain, whose website is just awful - awful! - but who provide what appears to be a decent product. I bought some of their "extreme", which is apparently a Zoysia-like grass; low maintenance, low water requirements, very strong spreading tendencies, goes dormant if temperatures drop below a certain threshold. To us, it seemed perfect.

My issue is that I ran out of the fertiliser that we first bought with it, and I'm finding it hard to find out what I should be feeding it with. There seems to be so much conflicting advice. I'm somewhat disappointed with how little it's spread over the last few months, and it still looks very much like a series of slightly larger plugs rather than them showing much sign of "filling in" as I had hoped by now. I'm watering it three times a day, and was feeding it every two weeks until the fertiliser ran out. I'm hoping that it will start to perk up and spread well now autumn is on its way, as we get a second growing season in these months where everything that was struggling over the summer springs back to life.

This is a rather long-winded way of asking for advice on the composition of the fertiliser. I want something that wil encourage spreading, so I assume both root and leaf growth, but I've read conflicting information on what the profile should look like.

I have a friend driving out from the UK with a van in a couple of weeks so this is my opportunity to get the right fertiliser rather than simply what's available here, which is rather limited choice.

I'd appreciate any help.

Thanks