Just received a Wahl Desk pen fitted with a Wahl Oxford No 2 nib (The pen is very similar to Doc Nibs current offering & it is gorgeous)

It was a dry writer but I've adjusted & improved the wetness. It responds to pressure variation but I'm not sure whether its classed as a flex nib .. perhaps fim flex would be appropriate description.

In any event the nib is a fine to extra fine nib & I think I'd be happier exchanging the nib to a more medium size nib my question is how to go about it

1. Buy a new nib & try swapping myself ? ... No idea what to do really, the nib doesn't want to unscrew & I don't want to force it.
Would I have to order the same type of No 2 size nib or could another size nib be used on the section feed? What are the possible costs & availibility of nibs to fit?

2. Send to someone to get the swap over ? ... Any idea who to send it to & possible costs

3. Could the nib be easily retipped to a medium?

I have no objection of sending abroad but it would be nice if I could get someone from the UK to work on the nib.

All advice gratefully received

Thanks