I think its good if you want to work in-house long term, and especially if you have an interest in financial services or the insurance industry.
Moving to private practice is not going to be straight forward if your experience is mainly in-house, even with a six-month secondment to a private practice firm. You will be competing in a job market where people have mainly worked in private practice. Those people will have worked with a broader range of clients, have gained work experience across practice areas and got used to more private practice process knowledge like business development, time recording etc.
It is not to say it will be impossible, it just will be more difficult than if you have trained in private practice. It may be more possible for firms that have a financial services/insurance sector focus, because your sector knowledge may be in more demand.
People may think it might be easy to impress on a six month secondment to the private practice firm and potentially be hired by them, but sometimes there are terms in secondment agreements that restrict firms/in-house teams from nabbing talent from one another.
