I've always been interested in moving to France to work as a gardener.
In terms of employment would my UK NPTCs in pesticide (PA1/PA6) and chainsaw and tree climbing be suitable to get a job.
I have seen a number of gardeners from the UK take Head Gardener and other positions in France, including the prestigious Giverney Gardens (Claude Monet's home), so I assume they have found their qualifications tranferable.
Good luck following your dream.
Colin Elliott - A Gardener in France http://gardendesigncompany.wordpress.com/
Taking full time employment is, as Colin says, not a problem and British gardeners are sought after - although people tend to assume there is only one style and technique to British gardening. Self employment is whole different matter and very complex, made more so after changes in January this year.
Your qualifications are all valid and would be recognised - higher qualifications can easily translate into the Bacs system. Specific Skills and Research is the difficult part, there are surprising amounts of land management techniques which are alien to the French and vice versa.
Most British gardeners, and I think Phil Voice would be best placed to state whether this is the case, tend to stick to clients within the English speaking community and from those I have met have a wonderful lifestyle but are not rich.