You've got the job - now check your new contract of employment:

Job Title
did you know that this is actually a legal requirement? Make sure it's there and that it matches your expectations. Beware very loose and flexible job descriptions. Phrases like "and other duties as required by the company" give your employer the option to change your job as they wish, regardless of what you want from it or how well you are doing.

Probationary Periods
Typically, these specify that you need be given only one week's notice of termination during the first three to six months at a new job. They are used by employers to limit their liability on risky hires - trainees usually. If you're coming from a good job you could negotiate to have this shortened or removed.

Notice Periods
Take as much notice as you can get. When you resign, you must offer to work your notice period. If not, the company can refuse to pay you for this period. They can only make you work your notice as gardening leave if there is a clause in your contract allowing them to do so. 

Holidays
Your annual leave should be quoted exclusive of public holidays, or else your 25-day quota might really equal 17 days.

Armchair Experts
Every contract is different. Get proper legal advice.

Final Words on Resigning
Be professional and pleasant, but firm. Have your resignation letter ready. Don't burn your bridges. And don't even think of taking company records with you: that's stealing.

Last of all if you are still unsure please contact us for more advice.