Servicing a bike left in a garage Knowing next to nothing about bikes I bought a Parva hybrid bike a few years ago, which saw only a few rides before being put in the garage to collect dust. Now that I'm moving to a new city I need to get it back into working condition.

Is it worth taking it to a bike shop (halfords is near) for a service or is it likely that I can do most of the work myself using some sort of guide?

Cheers
Bicycle maintenance is well within the scope of most people with basic tools. Your task is made easier because the bike had not been ridden many miles before being stored, so it should not have any significant wear and should still be adjusted correctly. Bicycles don't wear out or go out of adjustment when they are just sitting in a garage.

You can go through a basic list of checks then if you find a problem look further guidance here or from other resources.


I always recommend cleaning the bike thoroughly including the sprockets and chain as it makes maintenance more pleasant and is a chance to visually inspect the bike.
Inflate tires to recommended pressure. A puncture will be readily evident (although check the next day for slow leak). Tires or tubes may be dried out and cracked. If so you can replace them. 
Check that both brakes are working properly. 
With the rear wheel off the ground manually spin the cranks and change through the gears (getting someone to help you makes this much easier). Spin the wheels, cranks and pedals and make sure they rotate freely with no looseness or play in the bearings.  
Make sure shift and brake cable housings are inserted properly into shifters and derailleurs, levers and calipers, and attachments points on the frame.  
Go over the whole bike making sure everything is attached properly and not loose. Seatpost, seat, handlebars, stem, pedals, brake levers and calipers, shifters, derailleurs etc,
Make sure wheel quick releases are done up properly.
Re-lubricate the chain.


Update, some links to Park Tool Company pages on the most likely adjustments you may need to make:

Front derailleur adjustment

Rear derailleur adjustment

V-Brake setup