I have got some frontline for the Tedster but it says on the packet it's for size as opposed to age (i've got the smallest dog one, think 2kg - 10kg but don't have it on me so can't be sure those weights correct). So is it okay to use it then?  He is 16wks.  Should they have given me a puppy-strength treatment?

Yes, the spot-ons are done for weight, not age. Regular frontline spray can be used on puppies from 2 days old, so your pup is plenty old enough.

brill, thanks Jeangenie.