I don't think they are F1 - I've looked at two different seed merchants and neither indicates F1.
Have you searched your local garden centre? I bought my tumbling tom plants there. I think you're likely to end up paying quite a lot for plants e.g. T&M was £4.99 (plus p&p, presumably) for a single plant in a 8.5 cm pot, or (7.99 for 3 jumbo plugs, or 8.99 for 3 x 8.5cm pots).