Best place for savings?

I have moved away from the area and now rent out my house to a friend for £675 p/m. I am currently able to live without using this money and up until last month it was in a NatWest savings account. I have since placed the money into savings bonds which I plan to add to each month.

My question is whether this is the best place for it? I want to be able to have access to it and withdraw it if I need to but also to make the most as it's just sitting there at the moment until I withdraw some for my tax return.

Thanks