in Northampton aye?
Lets start from the top :)
What size can you fit in?
What is your budget?
Whats your long term goal?
Anemones are one to stay away from till your tank is mature. Bubble tips are the easiest to keep, but make sure power heads are covered so they can't go on a suicide mission. AGAIN MATURE TANK ONLY!
No idea on the book front. Have a search on here under the QA section, you will find a lot of useful information.
Clown fish are a good start fish, most people have them in a marine tank as after all, first fish you think of when marine is mentioned is a Clown
Clean up crew is important with a marine tank! Snails snails and um snails!
Rock, you will need live rock ( dry rock can be used but i won't get into that! ) Go for 1KG per 10L of water as a rule
Live sand isn't needed but can speed up the cycle of a tank, but if using live rock then coral sand will do fine ( and cost less ) 1-1.5mm is a good grain size.
Skimmer is up to you! plenty out there and bubble magus are a good cheap skimmer ( model depends on size of tank )
Heater, again depends on the tank size. 200w is good for a 3 foot tank. i'd go for 100w per 100L of water as a good rule.
Wavemakers! Need at least one of these. depending on corals to what size you need. I have roughly 6000lph in my 3 foot and that's on the low side for what i keep!
Lights, Depends on the corals you want to keep. You can spend a £150 on a light unit or £1500 on a light unit. LED's are getting better by the year, and are recommended.
Refractometre is a must! For checking salinity
RO For topping up the tank to keep the salinity in check.
Salt water for water changes!