Dual Flush adjustments question?

[hunterxf382]

Hi there, I'm a newbie on here trying to get some sound advice from those with more knowledge than me....

I have a dual flush loo of unknown make (possibly from Plumb Depot but brand unknown). Recently noticed that the overflow was flowing into the bowl from the cistern. Did some searching online, but not found where to adjust the float level with this particular model. Cannot see any obvious means - so i'm hoping someone can assist please?

After either flush, the cistern is filling up as far as the oveflow (if that's what can be seen shaped like a crescent in this next photo:

I'm not particularly impressed with these dual flush models - the mechanism's look too fussy compared with the traditional, where at least you could see how it worked and fix easily enough...

 

[hunterxf382]

Anyone able to help please?

 

[seco services]

have a look under the cister on the mains pipe for an isolation valve so you can work on the float.
don't know that valve at all.
all they basically are is a plastic float that you can adjust.
can that top blue cover come off ?

 

[hunterxf382]

That blue top looks sealed, maybe seperate when made but not obvious how to remove now?
Also I have no isolation valve - such is the quality of the plumbers work here...

Anyone recognise this float valve type?