If they're old or classic any guide like parkers of glass is going to be a waste of time, values of classics fluctuate abit making it hard to pin down a true price, unless you buy/sell them it can be tough to gauge market value.
find out what your solicitor would consider as a 'value' and then speak to the right people.
find out what your solicitor would consider as a 'value' and then speak to the right people.