You've been unlucky Gem with the wills not being on Family Search. It's been a number of years since I got a will from the Manx Museum. I used to e-mail them to tell them what I wanted, they would then give me a quote and I would post them a cheque. The last time I got something they e-mailed it to me. You could e-mail them and reference the will index details of the 1898 will and ask for a quote for a copy. They should be able to send you either a paper copy or e-mail it to you. You could try this e-mail address:-

enquiries (at) mnh.gov.im