Nope, Upton on the Wirral =)
Before trying things to fix the short luteal phase, try to get confirmation that you do indeed have a short lp. If you start messing around with vitamins and stuff before you're certain you might only make things worse.
Are you temping at the moment? If not, I suggest you start =) If you take your body basal temperature every morning you should be able to tell from there, combined with checking your cervical mucus and maybe using OPKs, when you ovulate. Once you know for certain you've ovulated (which can be seen by a sudden dip in temperature, then high temperatures until AF comes in) you can count the days from ovulation until AF to see what the length of your luteal phase is. 'Normal' is around 14 days, though you should only start worrying if it's less than 10 days, as that would lower your chances of pregnancy.
So for now, I suggest checking that first =) It's possible you just ovulate early, around CD10 and have a normal luteal phase.
Sooo ... plan of action, which you obviously don't have to stick to if you don't want!
Wait until the first day of your AF, that will be CD1 (I'm sorry if you already know all this [you probably do] and I'm just repeating everything. Start taking your temperature at a certain time each morning, before you get up and do anything (that includes talk, breath through your mouth, walk around etc) and write it down (or use fertilityfriend.com to keep an eye on it for you). Do this every morning, at the same time as soon as you wake up, and make sure you've had at least 3 hours of sleep for it to be accurate.
Once you stop bleeding, start keeping an eye on your cervical mucus. Around the time ovulation is due it should turn into an eggwhite substance, stretchy and most often clear. This combined with a temperature drop could signify ovulation. If you want you can also start using OPK's (cheapies you can get online) as soon as your cervical mucus starts getting stretchy, once you have positive OPK you know you're about to ovulate or have just ovulated. Same goes for the temperature drop, this usually happens the day after you ovulated.
Once ovulation is confirmed through temperature and cm (and maybe OPK's if you're using them), start counting the days. If you're using Fertility Friend and your temperature has been accurate through out the whole cycle, it might pin point when it thinks you ovulated and you can compare that with your own guestimate. If AF shows up 12 - 16 days later, you're just fine to keep on trying and not worry. If AF shows up 10 days later or less I'd advice trying for another cycle to confirm, and then going to see your GP as you could have a luteal phase defect.
Did you have any trouble conceiving your 7 month old? If not, you probably just ovulate early rather than have a short luteal phase. But just to make sure it couldn't hurt keeping track of when you ovulate for a couple of cycles.
--Edit--
All that said, the whole no bleeding with ovulation is what my GP told me. If it's wrong, blame him =P
And when reading google just then, apparently it's quite common for women who are breastfeeding to have shorter LP's. So it could possible have something to do with that. If so, it's likely that your cycles will return to normal once you start breastfeeding less, or even stop completely.