How long is a piece of string?
There's water charges, community fees, wear n' tear costs, etc. that would be associated with any house. These vary in UK/Ireland and they also vary in Lanzarote.
Then, there's the question of whether you'd be renting out the property when you're not on the island. According to some, you should be registered as a landlord with a commercial property even if you only allow family to use the property.
And maybe a dozen other considerations...
Talk to a few different Estate Agents on the island. Then buy dinner/coffee for some people who own a property here - be it a holiday home or not - and ask them for advice.
HEALTH WARNING: Believe half of what you hear in person, and even less of what you read on web forums with regard to buying/letting property