I have BT Total Broadband Option 3, which comes with Home Hub Phone, which gives me free evening and weekend calls

I also have Option 2 (l think) on my land line, which gives me free evening and weekend calls as well..

Can l save a few pennies and downgrade to Option 1 on land line?

i had the same issue but i was in contract with a special offer on the std landline and couldn't do it ring bt and ask

Yes.

And use all your "Friends and Family" numbers for mobiles (Dial using the prefix '5' to route the call via the land line).

HH