Promotion:

Weekend: 4 * £50 Free bets 5 bets between each qualifying bet.
Week day: 4 * £25 Free bets 5 bets between each qualifying bet.

Multipe account detection: The best. Cookies, IP, post codes, names, linked accounts. Be very careful when opening accounts and especially careful when opening multiple accounts.
Concession conversion: Fairly easy , especially on football and horse racing. Best odds guaranteed on horse racing and non 5p deduction as an added bonus.
Account closure/restrictions: The worst at restriction account to a liability of £30. Be careful and use bets wisely.