not sure mate. i know that there is an NVQ level 2, but i dont think it is worth the paper its written on. it wont be recognised by employers. the only quals an installation spark needs are, a technical cert of some description, to at least level 3, and a qualification proving practical experience, such as an NVQ, or apprenticeship papers. of course you need to be cobncversanmt with the wiring regs, and there is 2382 for that also.
as your knowledge and experince progress, you can takle additional courses such as 2391-1 inspection and testing, 2391-2 installation design, ONCor HNC in electrical engineering, abnd there is now an NVQ 4 in building services, which you can specialise in the electrical part.