transfering qualifications?

Hi ......My other half is thinking of training for something manual like tiling.... carpet fitter.... plumber or plasterer or a locksmith...so we would be able to apply for the visa, as at the moment we have jobs that are not on the skills list,

im unsure of how the qualifications transfere ie when you get the qualification overhere,(england) what do you need to do to be able to be recognised as eligable for the job over there... is there a named qualification we should be looking at like nvq or btec? or do you just take the qualls over with you and get assesed once you are in a job...?

i know there are a lot of companys offering to learn you the trade in less than a month and at very little cost but its no good if the qualification means nothing over there...
can anyone guide me to a web sight maybe or tell me what the qualifications are called over there?
sorry to be a pain, im just so confused!

claire and darren