Geoffrey,
If you have smell of gas and you are not able to identify the source or correct it then you MUST seek proffesional help.
LPG is wonderful fuel but it must be contained properly. A leak is a serious matter and must be stopped for your protetction and others.
Do not wait, get it checkd and put right by a qualified fitter. Your insurance may be void if having smelt gas you have not acted to prevent it leakage.