6x3 = 18 hours played
6.50-1.36 = £5.14 profit
5.14/18 = £0.29 profit per hour
0.29 = 14.5 big blinds per hour
14.5BB per hour means you are currently running very good.
For example, if you were playing at this rate at £1/£2, you would be making £29.00 per hour.
Regarding the stakes you want to gamble at... that is a personal thing and depends on your own finances and experience. Personally I never buy-in with any more than 5% of what I am willing to gamble, so if your bankroll is <=£80 then I'd advise to stick with your current stakes until it gets there and then maybe take a stab at £0.02/£0.04 if you want to quicken up the progress.
If the progress still seems too slow, it is better to multi-table than to risk your bankroll at one higher table. This is because, if you can't beat the variance at 0.01/0.02 consistently, then you certainly won't be able to do it with higher stakes and even less of a bankroll.
But in short, you are currently doing very well. It could be luck, it could be skill, it could be both. Stay patient at your current stakes and we will see. To put things into perspective, even 1BB per hour is a good win rate in poker.