You'd have two options here.
You certainly could attempt to strike off. You will need to cease to trade for a period of 3 months, and you will also have to write the creditors (regardless of where they are located) to inform them you are attempting to close the company via a strike off application. Failure to do either is considered an offence. Please note that creditors have the right to object to your attempt to close the company in this way. Given the values, I would guess there's a high chance at least one of them may object.
For help with this, the following template letter from a debt charity is helpful:
Use this letter to tell your creditors and members of your limited company that you are considering strike off.
www.businessdebtline.org
The following step by step process from this forum can also be helpful:
CLOSING AN INSOLVENT LIMITED COMPANY WITH INSUFFICIENT FUNDS WITH WHICH TO PAY AN INSOLVENCY PRACTITIONER If a company is unable to carry on trading due to becoming insolvent the standard procedure for closing it down is for the directors to appoint an Insolvency Practitioner to liquidate it...
www.ukbusinessforums.co.uk
If the creditors do object, this will keep the company legally open, and the creditors could continue any appropriate debt enforcement action.
Alternatively you could explore a Voluntary Liquidation, but as I suspect you've guessed, you would have to fund the liquidator's fees in this case yourself. The positive with this option is that creditors cannot object, and the company would be closed within a matter of weeks. For more information about the liquidation process, see the below:
Creditors Voluntary Liquidation (CVL) is a formal insolvency process to close an insolvent company. If your business is struggling, contact us
www.wilsonfield.co.uk
In summary, you could consider attempting to strike off first, ensuring that you notify creditors and cease to trade for the required 3 month period first. If any of the creditors do object, perhaps then would be the right time to consider Voluntary Liquidation. Should you need advice and quotes for this process, I'd be happy to offer a cost free and no obligation consultation by phone.
Hope the above helps!