The Tells were common prewar break barrels made by Oscar Will. Yours has no barrel lever lock so is the break barrel model made in small numbers until 1939, according to Dennis Hiller. The trigger looks like a crude replacement one and the adjuster screw is missing. If complete and in full working order without cracks in the stock, good examples of these rifles can be worth over £100. At a guess I'd say someone might pay £30-50 for yours.