In my last house......i used the trades that were already working on the house to fit the kitchen.....they fitted it, in about 3/4 days.
Chippie, i was paying £150/day......but bloody good and didnt cut corners....he basically did most of the fitting.....i was amazed how he fitted the work tops and did the joints.....no glue or rubbish like that....
he bolted them together.....you couldnt even feel the join with your finger after he'd finished.
I had a plumber on site as well.....for the dishwasher/washing machine plumbing and sink. Think he was £100/day
And then an electrician.....think he was about £130/day
Soon mounts up tunnie.....but that was when trades were hard to find.....in this economic climate.....i expect trades are falling over themselves for work.....and expect their prices have dropped.
Be better to buy the kitchen and get your own trades to fit 
Basic stuff i can do, i would fit the kitchen myself, plumbing is easy as well, worst i can do is get wet 
Leccy stuff i would leave to a professional though 
any electrics in a kitchen have to comply with building regs. not just part P (electrics) but also the parts covering Access (think its M) Ventilation (not sure), Fire, Sound (cant go cutting holes in the ceiling willy nilly anymore!! And then there's any Gas safety issues too.
If you're gonna do it yourself then you have to notify building control and get work inspected at various costs.
I'm fed up of finding kitchen botches and it's no wonder with all these extra charges to keep them safe! I find botches both from ignorance or from poor professionals. On the sparky side, even being 'Part P' certified is no guarantee of a good job. References are a must for any fitter!
as for supply, mine came from Alno. the best quality i've seen in a kitchen for a long time. All the mountings are stronger, the feet are bigger and tougher, the draws and carousels work and the whole lot came ready constructed to just bolt together. The worktop came ready jigged too.
It's definitely the final finish that can make or break a kitchen install, whether pro or DIY. take your time, ask lots of people who know, not who sell, and don't cut corners!!
