I got the bar off and there is a little rubber black knob that covers the space tab, I must have pushed it to one side whilst sliding a piece of paper underneath the tabs to remove dog hairs. Not realising what it was then proceeded to use the blower to blow it into a brown shag pile carpet, how I've found it goodness knows how but it has been put back by a drop of glue and does work very gently by one finger until the glue dries. More to the point you 3 people have saved me £25 for a guy just to look at it. Thank you for taking the time to answer my question.

Time for a well earned morning brew.
To the mods, where is the little smilie 'I love Talk Photography'