Your plan isnt really realistic in todays climate. Firstly on a property of £100,000 you can expect to pay £10,000 or more in taxes and legal fees. You would get a mortgage of 70% as a non resident whgich leaves you with a balance of £40,000 (70% of £100,000 plus 10% taxes)
With your budget then you would be looking in the region of £50,000 – £60,000 with a mortgage. Thats about 100,000€. Try checking what you will get for that. – Diddly squat in anywhere where people will want to rent out.
For decent rentals only one thing is important – distance form the beach – everything else is secondary but if you buy 40kms from the beach dont expect to get more than a fortnight a year bookings and you wouldnt be able to charge a lot either.
Also you are unlikely to find anything on the main costas – even the costa Calida would set you back €120,000+ for a 2 bed apartment.
Also unlike the UK the long term rental market isnt an attractive option as anything over 11 months and you run the risk of losing your house to the tennant and it will be difficult if not impossible to shift them -= especially if they have children – forget getting your house back. And I speak from bitter experience (I did get my house back in the end but it took a lot of trouble and courst visits to do so.)
Sorry to dampen your ardour but there are a lot of rental properties around and fewer rentals as well as cheaper hotels – all this adds up to a depressed rental market and a depressed property market.