It's too bad your not down the road from me, I'd do your laptop for free!!! The material your laptop is made of is Anodized Aluminum. They engrave very easily. The guy your trying to get to do the work for you is probably just scared of f--king it up!
As far as buying a unit, the ones I sell are made by Universal Laser. The chinese lasers are crap, unfortunately. The laser tube they use is made of glass, and they fail after a few months (6 months max). You have to remember your parts come from China, so they take up to 3 months to get here (not sure about the UK). I know this because we have quite a few people call us wanting us to fix their chinese made lasers. The Epilogs are ok, again I may be biased because I sell Universals.
One thing you really must consider when buying lasers is the actual laser tube itself. All self contained lasers will eventually need to be replaced. The epilogs are a pain in the ass because you have to send your laser to get fixed, and when they fix it they only fix what is broken. And then they send it back. It takes a lot of time, and can buy in the neighborhood of 3-4 grand.
With the Universal's the laser is part of a core system, where you order a new one, it is shipped to you and you swap it with your used one. Usually they are available for next day shipping (in the US).
If you decide to buy, you can buy from me and I can come out and do the training!
I hope this information helps, let me know if you have anymore questions.