What remedies are available in the last instance?

Bhutan Elections Act

241. The appellate authorityshall, upon holding an inquiry or hearing as deemed appropriate, make everyendeavour to decide the appeal within five days of its receipt.

242. The decision of theappellate authority shall be final and binding during the period of elections.

243. The decision of theappellate authority shall be communicated to the parties to the appeal and tothe Returning Officer. Provided that such order may be called in question afterthe completion of the election by means of an election petition in accordancewith the provisions of this Act.

244. The Returning Officershall, where the appellate authority accepts an appeal, forthwith suitably revisethe list of contesting candidates to give effect to the decision of theappellate authority, give notice of the revised list to all contestingcandidates and publish a copy thereof in the same manner as prescribed for thepublication of the original list of contesting candidates.

Source:http://www.election-bhutan.org.bt/wpcontent/uploads/2013/04/ElectionActEnglish.pdf