My vet has said my old shire need to put on a bit of weight but the tape I have is not large enough. does anyone know where I can get a tape that is over 750kg
Just use a regular tape measure and do the maths conversion. I can't recall off the top of my head, but it will be easily googleable - I never used a purpose built weight tape!
Ditto above, use a regular tape measure. The tapes that state the weight in kg already are not accurate. If you cannot find one then measure his girth and length in cm and use this formula:
Weight (kg) = ((Girth2 x Length (cm)) / 11877
Girth2 is meant to be girth squared but I can't do a superscript character
Obviously this method is not 100% accurate either, however more so than looking at the weight stated on a weigh tape.