Well being part of a group is going to effect things there greatly Dave. If you remember rightly Geoff it use to be Bristol and Weston health authority and it also only required 1 or maybe two people driving up from Bristol to look after it. Only when it was treated as a stand alone unit was that number too little. Also yes condition of equipment also plays an important part.
If you think four is frankly ludicrous you should see some other hospitals this size, my colleague went on a training course to another trust recently and hasn't stopped talking about how many people they had!