Firstly, what should I expect from my employer in terms of what they'll supply me with in terms of tools / petrol money etc?
You should have ironed that out before committing to join. Not sure whether they have any obligation to provide you with either, you'd have to check with them and/or HMRC.
If i employ someone i expect them to buy their own tools including power tools but some firms will provide you with them.
Secondly what are the essential tools I need, what are the best brands and where can I get the best prices?
Best prices: Amazon and Screwfix.
Best brands is all personal preference but i like to go with German hand tools and DeWalt powertools, although the Milwaukee stuff is awesome too. Favourite hand tools are Klein, Gedore and Knipex.
Finally, what's the best way I can start prepping? I'm ok with DIY but feel a bit like a dunce when it comes to knowing the basics! Maybe buying some sockets and practice wiring them up (with dead wires if course!)?
The absolute first, essential thing you must do is, go and buy a proper voltage pen (NOT an illuminous screwdriver) AND a voltage/continuity tester. I have the Fluke T90, 50 quid (they're actually £39 on CEF right now not including postage) on Screwfix but has saved me from a few belts. Then learn how to test for incoming AC power. Test every circuit you're asked to work on even if the breaker appears to be off and especially if someone else has just told you it's off.
You'll need a copy of either the EAL Level 2 or the C&G Level 2 book for your college course depending on who the awarding body is. Start reading through them. Get familiar with stripping wire with a pair of side cutters. Practice getting the lengths right and how to terminate correctly eg no copper on show but no sheathing caught in the terminal.
Start practising how to pull cables through into awkward places. There's an art to cable pulling and you'll be doing a lot of it.
Get the basics of how wire size and breaker sizes combine and work together for safety. You probably won't need to know this off the top of your head until year 2.
Learn about radials, ring finals, lighting circuits including 2 and 3 plate methods (whether the feed is taken through the switch or directly to the fitting).
Really, there's no much more you could do than that in preparation for September and really they won't expect anything else from you. Just be keen, do what you're asked as long as it's safe, and don't use your phone at work and you'll be golden.
I passed my trials to get into the industry because i don't stand about on Facebook all day and i'm keen to get the job done so we can all leave earlier. Show willing and you'll be golden.
EDIT for practical skills like wire lengths and termination styles etc check out GSH Electrical on youtube, solid gold.
EDIT 2 READ your apprenticeship contract fully and thoroughly. An apprenticeship is a decent opportunity if the company is good but some will try and have the mick out of you. The take home points are you're allowed dedicated time AT WORK each week to study, off the top of my head it's an hour a day but check your contract, and they HAVE TO PAY YOU for going to college irrespective of your age. Any other training must also be 1. paid for by them and 2. you must be paid for attending. So your firms overtime rates for Saturdays is time and a half? And they want you to go on an IPAF course on a Saturday? Then they must pay for the course and pay you time and a half for attending it. Some firms try and get away with not paying for these.
By year 2 you will have enough skills under your belt to be able to go work at the going rate for an improver which is around double what a second year apprentice is on. Up to you whether you decide to go that route then and build up 5 years experience so you can do the 'Experienced Worker' route - become qualified without working on slave wages, or stick with the apprenticeship.
After 4 years on minimum wage on an apprenticeship you'll come out 'fully qualified' but you'll only be on a quid or 2 an hour more than the agency improvers on site. Personally i went the improver route because staying as an apprentice on minimum wage would have cost me roughly 66 grand in lost wages. I'm now on more than a lot of sparks i know. People covet apprenticeships as the gold standard but really the only relevant thing is
who taught you? If you got taught by someone who's rough you'll be rough without knowing it. And trust me when i say most apprenticed sparks i know are rough. Usually i find the older lads who got into it because they really wanted to have more dedication to finding out the proper ways of doing things and as a result their work is usually much better.
When it comes down to it, if you have the NVQ, Inspection and Testing and the 18th edition, hardly anyone cares whether you were an apprentice or not.