Just out of interest - What was the item you bought and when did you send the cheque ? Seller won't send until cheque has cleared - Has it cleared ?
You say the goods are not exactly of "High value" - seller hasn't sold anything for less than 50 quid in the past month or so as far as I can see.
2 out of 3 of the sellers current items for sale are to be sent via Parcelforce48. Consider that the seller MIGHT be genuine and the courier has lost the parcel - especially if Parcel-Farce were used
If it WAS sent via them there will be a record.
You have the sellers name and address from sending a cheque so ask them ( or other courier if you know who was used ) to investigate.
The seller already has 2 Negative feedback reports against them, so one more and they will risk being suspended from trading - I would file a report to E-Bay ( Go through the Help menu's following various links for reporting Fraud / Paid for Item and not received it - then select the "Contact us" option - DO NOT fill out any of the standard forms as it will only generate a standard reply and no action will be taken ).
E-Bay should then contact the seller and warn them / investigate which may prompt a response.
As for getting your cash back you could also consider a fraud complaint to your Bank - if the cheque has been cashed it has been paid into an account in that name so can be traced.
GOOD LUCK !
