Yes, I would plant some indoors to get them started, about now or in the next couple of weeks. If planting outside you need to be sure that the danger of frost is passed and the ground is resonably warm.
If you cover them with fleece you may get away with planting outdoors in early to mid May.
I would stagger planting so that if the early ones do get hit by frost you can still plant more.

Many thanks that is most useful and confirms what I thought. We were going to plant some indoors yesterday but I thought maybe in 2 weeks would save them from getting 'leggy' as they do sometimes indoors.