In a bit of a pickle!

atush

I think 5K in cash, with 3 homes is too low. Also Isas are low with only 15K between you.

JonathanBFS

Sell the BTLs your only going to pay tax probably on rent in the future, invest tge equity in pensions and S/s and go live comfortably in your boat if this is your Income needs!

CookieMonster

.... the plan is/was to travel and live off the rental income. 

You're in a pretty good position with the SP not too far away.
If it was me, I'd sell the houses (yes, they're an income but they also require 'work' and can be a liability, bad tenants for example), invest the money and do the travelling/whatever you want to do as soon as you can.
We don't know what may happen tomorrow, don't put off your travels/plans too long.

Snowdrop08

Thought I’d post an update. 

Well, just as CookieMonster alluded to-life took an unexpected turn!

Long story short-we ended up selling one property to clear the mortgage, invested the £30k “profit” and are now lucky enough to be travelling around Northern Europe for a few months. The boat has been “ home” now for quite a few years; great in the summer, not so much in the winter! 

We’ve had a very difficult few years, like many other people and relish the freedom of being mortgage free. (And not having to deal with the letting agent!)

When we return in late summer it will be back to POA duties and a bit of part time work (which I love). 

There’s always next year!