Mike does the seller have a phone number in the ebay listing? If not, you should be able to get their contact details including phone number from ebay, especially as you now have an order with them. IMHO, there's no excuse to ignore questions from potential buyers, looking after the customer is business rule #1 (well, if you want to stay in business anyway) but some ebayers seem to be good at dumbing down their computer skills...... never a problem listing items for sale, but won't respond to Q's.
All the same, a good feedback rating should give you confidence, benefit of the doubt and all that. If you pay through PP or with credit card, you should be able to get a refund if it does turn out to be problematic.