I have now shipped thousands of items from E-Bay and othe sales to all over the globe from Peru to Poland and from Tasmania to Torquay !
I am happy to share my experiences.
Shipping in the UK.
Simple rule. Less than 4KG use Royal Mail Standard Parcels or 1st class.
Over 4kg and with main dimension less than 110cm use one of the many comparison sites such as interparcel.com or parcel2go.com or parcelmonkey.com. They will give you options. In my experience AVOID Hermes. They have been completely useless to me. Have lost, broken or just not delivered items. Yodel are OK and cheap but if you have a problem they are really difficult to deal with and actually lie to your face ! Best of the cheap ones are UPS. Especially if in conjunction with Interparcel.com as the "broker" site. UPS have been totally reliable and always show up when they are supposed to.
For large parcels ( over 120cm ) the best seems to be parcel-link.co.uk. They use City Link and beat all on big or heavy parcels.
Another simple rule: Royal Mail for anything less than 2KG and with a combined dimension ( length + width + height ) of no more than 90cm. Small box to Peru for £2.50 !! Beat that !
Over 2KG or very impotantly, over the 90cm rule, use either the above comparison sites or, the almost completely unbeatably, transglobalexpress.co.uk. You can ship most average size items anywhere in Europe for about £20. I have shipped an entire car interior with seats and all to Taiwan for just £130 ! Trust me, that is a bargain. However. Be aware: Transglobal often try to charge extra by saying that the parcel you sent is bigger than you said. ( All overseas shpments are based on Volumetric weight. That is the Width + Length + Height multiplied by a certain factor to produce a volumetric weight )/. ALWAYS photograph you parcel before collection. Most overseas parcels go with DHL or UPS or DPD. These offer the best value.
An example: Large Parcel sent to Malta, booked through Interparcel with DHL on Sunday night. Collected 1600 Monday, delivered to Malta 0800 Tuesday !! No idea how they did it so quickly and for just £30 !!
Shop around. I check at least 3 of the main sites to get the bills down.
I hope this helps some people.