I'd first check if I'd qualify for a BtL mortgage at the moment - I'm one of these 'accidental landlords' and while I have equity in my UK property, I don't have enough to qualify for a BtL mortgage. In June you were looking at around 20%-25% downpayment for one.
Also, keep in mind that if you are abroad you will have to have a local agent to let out the property and that'll cost you part of the rental payment. Most of the ones who I talked to charged between 10%-15% of the gross rental, plus additional fees for background checks, finding tenants and whatnot.
That aside, I think one of the deciding factors is how long you'd expect to keep the property. I would not expect any appreciation in value for quite a while and potentially, I'd expect that the house will lose value for a while. IIRC it took about 10 years or so after the last house price crash until prices recovered to the same level.
Now that we've got all of this out of the way, I have a few concerns about this idea. First, even if you can pull together a 25% down payment for the house (plus all the costs involved in buying a house), you'll take on debt in the order of 3 times salary on the speculation that you might get enough in rent (after the agent's commission etc) to cover the mortgage. What are your plans if that doesn't work out? You'll most likely not be able to cover the BtL mortgage and the rent or mortgage on your own place with your income. That's a heck of a lot of risk for not very much reward.
Second, do you have an emergency fund in place that would cover the mortgage for a few months if you're out of work? Or pay for a new roof when the tenants are fed up with covering the whole attic with buckets?
Basically, I think that it'll be a close call to purchase a 100k property with a 25k downpayment as your primary residence on your income and I think you might be signing up for a whole lot of financial pain if you put all your 'investment' eggs in a single, house-shaped basket.