Sorry, but you're saying you're going to Guardamar for six months and paying £200 for travel insurance? That seems very steep. Direct Travel only charge us (same age group as you) £40 for annual insurance as long as we don't go for more than a month. Single trip for up to 6 months is quoted as £24.00. If, however, you have more than one pre-existing condition, they will charge more. Your EHIC will cover you for emergency treatment for up to six months but not for medication for pre existing conditions. Before getting too much medication and relying on the vagaries of the Spanish postal system, check out how much it would cost from a chemist in Spain. You don't say what type of meds you are on for blood pressure (ACE inhibitors or ARB?) or pain (co-codamol or ibuprofen or similar?) but you may find them cheaper than the prescription cost in UK. My son in law buys his asthma inhalers in Spain (£3.50 each as opposed to the six quid or so prescription cost in UK). If you bring either your repeat prescription slip or a box of the old meds and show it to a chemist in Spain, they will issue most medications without a Spanish prescription. My wife was on co-codamol 8/500 in UK after a knee replacement. These were cheaper from a pharmacy in Spain than on prescription in UK.
Unfortunately, over age 70 the price of travel insurance goes through the roof. Direct Travel won't cover you over 65. However, Insure For All quote £74.50 for a two week trip to anywhere in Europe for a couple aged 80 to 84 and £108 for a month but you need to call them if there are any pre existing conditions. www.travelforall.com
Try these first and I'm sure you'll get it cheaper than the quotes you have.