Hey,. Good choose on deciding to build your own .
The zmr250 is a fairly popular kit but the one sell for £75 is aimed at beginners so flies more like the runner 250 compared to the vendetta which is quite powerful.
As for building it we have a full zmr250 build guide - http://www.dronetrest.com/t/qav-zmr-250-assembly-build-guide/1244
And if you have any questions about the kit just let me know. And any problems building just as on the guide