Tourist and then Work visa?

I booked flights too fast and planned a trip to Thailand within the 30 days. It is coming up to Spring festival after all. Is it possible to use a double entry L type and then get the Z type somewhere nearby, say, in Hong Kong? Then I can just do the resident's permit on the entry from Hong Kong. My Invitation letter says apply in UK so I would have to ask my employer to reprint the letter to change the place of application but I have no idea if this is easy or reasonable to ask of him.