I use Lorraine Pascale's recipe:
450g tomatoes chopped
2 chopped chillies (use more if you like it HOT)
1 cm ginger grated
2 garlic cloves
250 g granulated sugar
60 ml balsamic vinegar
a little salt and pepper
Blitz all the ingredients together in a food processor and pour into a pan. Bring to the boil slowly, until the sugar is totally dissolved and then boil for around 30-35 minutes stirring all the time until the mixture becomes gloopy (about the consistency of Branston pickle). Leave to cool slightly and pour into a sterilised jar (1 lb size).
I could help with translating metric to imperial (only in the US apparently they call it 'US Customary Units'. I never knew the term 'imperial units' until living here; I think I called them 'normal' or something...). However, I cannot translate 'gloopy in relation to Branston pickle'. I don't go near the stuff myself. I would suggest doing for the consistency of jam.
Good luck - and thanks Vivien!