It's worth starting by drawing up a specification or 'spec', clearly setting out your requirements. Distinguish between what is essential and what is desirable.
You can then circulate this spec to likely sources of premises such as commercial agents who act as estate agents for commercial premises. Local surveyors who can assess the condition and value of premises may know of suitable properties in the area. Search for premises on the South Tyneside Council property database.
Check any potential premises against your spec and eliminate any that don't at least meet all your essential requirements. Then you can draw up a shortlist of properties to visit.
For more information on premises, see Business property
At this stage, you may want to involve professional advisers. For example, a surveyor can assess the condition of premises and give you an idea of their value.