Titan Telecom Anyone?

I'm looking for ways to reduce my telecom bill. Currently averaging £240 quarter with BT. Members of household have mobile phones and rarely use BT line except for occasional mobile call. I'm currently paying Unlimited Anytime and Broadband Option 3 at £140.
Titan Telecom is offering £15 per month all in which looks silly to me.
What I tried to get from Titan was an explanation as to what would be the physical trade off for such a low price. Do they switch me to a lower tier in the comms network for example?
I know nothing about telecoms but I rather suspect it is like most esoteric services where knowledge is hidden to the greater loss of the uninitiated consumer.
So, has anyone got some inside knowledge on Titan or any other alternative supplier that I should consider before switching from BT?

Their broadband is £20 a month and line rental is £9.99 a month, so £30 a month, or £90 per quarter.

The pricing is different to BT, with BT first hour of call is free on anytime, but with Titan you pay but it seems to be a capped price. So it might, or might not be cheaper depending on what calls you make.

Looking at their price comparisons you need to be very careful with their claims

So is the £240 PQ just line rental and a few mobile calls? as £80 per month does seem a little pricey, or is the £240 including the broadband?

The £240 Includes Broadband