hp sauce is quite often available in santo domingo (nacional and la placita are the last places i saw it, not sure if there is any left). last batch was about a month past expiration date, when i bought a couple of bottles at rd$119.99.
bovril may still be available in pola (lope de vega). that is a bit pricey, almost rd$300 for a medium sized jar. they keep moving it around to different aisles for some reason.
bottles of extra strength guinness are probably still available in carrefour (sometimes find the other odd thing of interest there)
there are ordinary digestives and other sorts of uk biscuits in most places. pola (lope de vega) did have some plain chocolate digestives one time. i think they came from jamaica. there are some german biscuits which are exactly the same as hob-nobs, if i remember correctly.
i have never seen heinz baked beans in santo domingo. perhaps there are, but i have never seen them, other types of american style baked beans are available, plus those campbell's pork and beans. heinz is an american co., but everyone knows that their brand of baked beans has to come from the uk.
just remembered...... in the chinatown area, you can see the odd uk food stuffs in their supermarkets. lucozade is one i particularly remember.