My blank carts should be here tomorrow and a cherry and menthol to try. I do not think I will be sticking with this kit though. I need something a bit more reliable when out at work.
I dunno vendors over there but there are UK vendors listed in the
Forum Suppliers section here. Reputable folk who are known around ECF (not that it's the only reputable bunch out there, just that it's a good place to start when you're not sure who's good and who isn't).
Filling my own cartomizers is working great for me once I got the "hang of it". Finding the juices you like and have the right nicotine level for you and whether you like PG or VG or what mix... that takes some experimenting. But when you hit the ones that really work, it's nice. Very nice.
One thing I suggest if you're using the "condom" method (what a name) is let 'em sit. I set up more than one. Let them really saturate for a while then pull them a bit up in the "condom" and let them stand. You can clear the excess
juice by blowing but that always struck me as wasteful. Not to mention messy.

I keep a bit of a "rotation" going so the excess drips back into the "condom" and the polyfill gets evenly saturated. I'll even set up a couple of the flavors I like in the mornings before I go to bed. That way they're ready and waiting when I'm stumbling around half asleep (I wake up really slowly, always have).
If you want to move on, I suggest taking a look at the eGo style of battery. Lots of vendors have them. Some are "variable voltage" like the Twist or the Spinner. I had a "cig-a-like" kit at first (actually, I ended up buying two in sequence before going eGo... spent more money than I needed to). The "variable voltage" thing can affect the taste and vapor too. That is, you can adjust to your liking. It can make a difference.
A kit I see recommended often around here is this:
Twist/Spinner Combo. Now that's a US company and I don't mean exactly that kit but it's the kind of thing I ended up wishing I'd bought first (I found ECF after I'd gotten a full kit... oh well, it got me going and I cut way back on smoking so it wasn't a "loss" really).
The 1000 mAh (and higher even) batteries last much, much longer. I like the Twist myself. Mine is 1000 mAh and I'm getting six or seven hours of use per charge (and I vape pretty heavy... I was a pretty heavy smoker also). I have two so one will be charged when the other runs down.
Also, the eGo style of batteries has dual threads. It can take 510 and eGo threaded attachments so you get loads of choices for the attachments.
tanks, clearos, cartos, bunch of directions to go...