I have a sharebuilder with Halifax, they give you a choice of a few days which you can invest per month, does it make any difference which day you choose?
I personally would not use HB for the same reasons.. I use Selftrade (Squaregain/Comdirect as was) and have had no problems with them. Halifax sharebuilder is also worth looking at if you wish to drip feed regular amouts and reinvest the dividends.
It's giving out free £30 food vouchers
This Forumite's mattress is in need of a base
Via Tesco Clubcard vouchers