I think 188 is the one where you have to contact live chat after your qualifying bet is settled to claim it.
For the two up PP offer, yes you need to lay it at the start, but if your team goes two up at any point, you've won at the bookies, even if your team goes on to lose at the end, pp have paid you as a winner so if your team goes to 2-0 at say half time, paddy power out the winning money into your account, there's no need for the lay bet at that point, because you have your paddy power winning already.
cashing out the lay means you get some of your liability back, plus the winnings at the bookie that's already there, without the 2up offer you need the liability because full match needs to played to see winner, but with 2up promo and potential for winnings to be in bookies before halftime it makes sense to cash out the lay as the only benefit in keeping it active would be for your team to lose after being being 2 goals up and winning bet at both ends. OM say it's very rare for this to happen though so it's better to cash out if you can.
I had an email off betfair saying I've been credited with a free £5 into my games wallet to use on their new "exchange games" section, with a X1 wagering. Had a look about and decided would use it on The exchange blackjack. I figured that it's the opposite of playing blackjack in that I wanted to pick the losing hand and lay against hands winning, so used the blackjack strategy on odds monkey and reversed it. Played at £1 a time and after the £5 wagering was done I had £10 which went to real withdraw able money. Five mins for £10 quid profit and no risk at all to me.
Have signed up to smarkets and have £7 profit their offer so a total of £17 today.