I've been suffering from achilles tendon problems for around 4 years and recently found a physio (not the first one I've tried) who has tracked down the source of the problem to weak back muscles antagonised by the rotation of paddling! At least now I know I am sitting up straight and rotating.
Problem found and solved in 3 sessions (35 euro each). I would highly recommend this guy to anyone needing bodywork.
His name is James Prakash BPT MAPA (sports) MISCP and he is chartered so you can claim money back if insurance allows. His office is in Carrignabhfear 087 6934442.
And no I'm not on a cut I'm just sharing the love
Don