Hi Paul they do prefer moist damp soil and are happy in boggy conditions. You can't really replicate this properly as in boggy ground the water is moving through all the time. In a plastic bucket the water would become stagnant and the primulas would die from lack of air.

You could just try a good sized, humus rich bed in the garden, Paul, in a semi shady position and keep it well watered in dry weather.

Thanks for the responses so far - this is such a useful site with lots of knowledgable (sp?) & helpful people

Ive bought some organic soil improver - would planting in this (rather than a mix of the improver and existing soil) and keeping it well moisturised be sufficient ?

Difficult to give a yes or no, Paul, but I would put a bit of soil and, maybe, some small (6mm) grit in the mix, mainly soil improver though.