trottr3 / HD / Jim - thanks for following up. I solved the carriage problem by simply screwing / unscrewing the unit back together again and on the 3rd or 4th attempt it worked. No idea why that worked but I then forgot I'd put out this plea.
Jim - I'll possibly need your assistance / wisdom in the future so will bear that email address in mind - and the 'coaxing'! Thanks again.